22Re Causes For Poor Mpgs And Running Rich?

[zero]

It might be my imagination, but I think my fuel mileage is slowly getting worse over time. This in my 1988 Minicruiser with a 22RE and automatic trans. I just noticed after our last trip that the inside of the tailpipe is coated with black soot. Not something I think I ought to be seeing with a fuel-injected engine - even with this crude system used by Toyota. It's hard to be sure if MPGs are actually worse due to the RV, or because of more wind during our last few trips. As fall comes, seems to be getting a lot windier where I go. In fact, an RV got blown right over on its side last week while crossing the Mackinac Bridge. 14.1 MPG was the best and 11.9 MPG was the worst. The first year I owned it, it averaged 14.2 MPG. Now, on our last trip - out of six tank fulls, we averaged 12.78 MPG overall. The RV is heavier now since I added a rear frame extension, carry box, rear spare mount, dual batteries, inverter, microwave, solar, etc. But it also has less wind resistance since I removed the roof-top air. I find it hard to believe it should drop this much.

I don't have a lot of experience with this sort-of "antique" EFI system that fires a half-charge of gas every rev of the engine and is not sequential. Obviously, since the engine fires only at every-other rev, one of the gas half-charges just sits there waiting to get used on the next stroke. Thus why I'm calling it "crude" by modern standards.

My check-engine light system is functional and it has never come on. I'm pretty sure that if the injectors were worn out, it is not part of the on-board diagnostics and no warning-light would come on as a warning. So, I'm wondering if one or two leaked and caused two cylinders to run rich. the other two might get less then needed to compensate? If so, the oxygen sensor would not "know" since it only monitors total output.

I'm just guessing. I put in a new oxygen sensor even though the old one checked out fine. It made no difference. Engine runs smooth and has good power. Only possible visible sign of trouble is the black soot in the tailpipe. Other then a few worn injectors, I'm at a loss as what can cause this situation IF it is running rich. I don't really know this for sure. Maybe it just overfuels when under a high load and otherwise OK. Does anyone else on this forum with EFI find black soot in their tailpipe?

The only other symptoms I have observed is when I shut down the engine hot, and then restart a short while later - it acts like it's a little flooded. Once I start it and rev it a bit, it clears out. That seems to be a distinct indicator of injectors leaking when the engine is shut off.

I guess an other possibility is a leaking cold-start valve. For now - I'm going to try new injectors. NOT so-called "rebuilt." I want brand new ones. I worked in a diesel injection shop for years and know very well that patched up used injectors sold as "rebuilt" do NOT perform as well as new ones. With many injectors with diesels - the moving metal parts can be replaced with new parts and that does make them perform like new. As far as I know, no new metal parts available for these Toyota gas injectors. I got lucky and found four brand new ones for $140 total. If my injectors are original, they have 148,000 miles on them. And oddly, 1988 model-year EFI injectors are different then any other year. 1987 and earlier differ, as do 1989 and newer. Why, I don't know.

Again - question #1 is if anyone else with EFI finds black soot in their tailpipe?

Question #2 is . . has anyone done an injector change and gotten an increase in MPGs?

[linda s]

I don't know about back tail pipe but my mileage always bumps up after I do a valve adjustment.

Linda S

[Totem]

Dumb question, but obviously you keep a clean air filter right? and Linda, if we were to have a mech shop charge to do a valve job how many shop hours is it? I am thinking I am due for valves, water pump, chain and belts.

[Gulfstream Greg]

Just a thought! How old is the timing chain? As they wear they get longer and the camshaft (valves) and ignition timing lag behind the crank shaft. You can re-time the distributor to the crank shaft but the valves are still opening late. Might not be a big concern but I see it as a problem at high rpm's. I have had 22r motors wear a hole through the timing case cover because the chain had stretched so far. Obviously ran much better after replacement.

[linda s]

Dumb question, but obviously you keep a clean air filter right? and Linda, if we were to have a mech shop charge to do a valve job how many shop hours is it? I am thinking I am due for valves, water pump, chain and belts.

I don't know how much a complete valve job would cost. I have just gotten my valves adjusted. Less than an hour job but my son-in-law does it for me so no money

Linda S

[zero]

Dumb question, but obviously you keep a clean air filter right? and Linda, if we were to have a mech shop charge to do a valve job how many shop hours is it? I am thinking I am due for valves, water pump, chain and belts.

I recently had a valve-job done because I was kind of forced into it. Cost me $1900 !! If I had I done it myself it would of cost me maybe $200 at most. THAT if I reworked the original head. I could of also bought a brand new complete head with new cam for $320 and another $20 for gaskets. I have most of the needed equipment in my own shop and do valve work for others (mostly big industrial off-road stuff).

My valve-job cost me $1900 which in my world, is ridiculous. But I'm spoiled and not accustomed to paying to have anything done (except for doctors and dentists).

I told this story before, but just to rehash the events. My wife and I were in the middle of moving from NY to MI. She was driving the Toyota motorhome and I was driving a 26 foot moving truck (with farm animals hidden inside). Before we left NY - I took the belts off the engine (22RE) and checked all the bearings to see how smooth and tight they were - in the water-pump, alternator, AC idler, belt idler, etc. All felt perfect. I also then put in new headbolts, new valve-guide seals, and adjusted the valves (timing chain was fine). Did a compression check and all four cylinders were perfect. Left NY and got near the PA border when my wife called me on the 2-way radio and said the Toyota was getting "hot." Well. before I could even reply - it was real overheated and steam was coming out. Ends up the water-pump bearing seized, fan broke off, went through the radiator, and the head-gasket blew. So, that was that. I still cannot figure how that water-pump got so bad, so fast - considering I'd just checked it a few hundred miles previous. So we got towed to a nearby repair shop. I begged the owner to hire me for a day as a "sub-contractor" so I could work on the rig myself, get it fixed, and also pay the owner even though I was doing the work. Nope. He said the labor laws are too complicated in NY and he did not want to take a chance. So there we were. The shop was not going to work on it for a least a week. We HAD to be in Michigan in two days. So we left it behind for over a month and then had to rent a car, one-way to drive 600 miles to come back to get it. In the mean-time, the guy in the shop called me. He had the head off and the engine looked fine. Even though the valves were also fine he said he refused to reinstall the head without sending it to an automotive machine-shop to have it "rebuilt." So, he used my gasket set and my new water-pump (had all that as spares with me) and the total job still cost $1900. Some of that was towing but we only got towed 5 miles so it could not have been much. Labor as I recall was around $800, so the bill on just the damn head was around $1000. Like I said - I could of bought a brand -new, ready to install head for $320 !!

I just completed two four-cylinder heads for a Deere diesel. Put in all new exhaust valves, new guides, etc. I charged the customer $450 total and that's TWO heads. Oh well, I hear these kind of high-price stories often from other people. I rarely get in a situation where I end up paying them myself - but this time I sure did.

Back to my engine and my possibly running rich issue. My timing chain is fine and air-cleaner is also fine. At this point - the only thing I can think off that could cause a rich-cylinder issue and have it not controlled by the oxygen sensor and NOT show up any check-engine-light errors is a bad injector or two. Just a guess. Since there is only one oxygen sensor - all it "sees" it the average fuel-to-air ratio for all four cylinders taken collectively. So two can be very rich and two more can be lean and the computer would not have any way of knowing the difference. It only takes an average reading of all four combined. I guess I'll know more when I put in the four new injectors. I'm already sure they leak since the engine gets a little flooded when the engine gets shut off. Fuel pressure remains in the system after being shut down unless it can leak off somewhere (like in leaky injectors).

[jdfrost64]

I have a 85 sun land express with a 22 re coming back from interlochen I noticed there was black soot around tail pipe. but also I have a 2004 Tacoma same thing. all of the Toyotas I've owned had this problem even the v6

[zero]

I have a 85 sun land express with a 22 re coming back from interlochen I noticed there was black soot around tail pipe. but also I have a 2004 Tacoma same thing. all of the Toyotas I've owned had this problem even the v6

Thanks for the reply and info. It might just be normal. It shouldn't happen with a carburetored vehicle nor should it with most newer fuel injected rigs. Even if the electronic controls let an engine run that rich under load, seems the soot shouldn't make it past a modern converter. But with a 1988? Who knows. I've got four new injectors ordered and guess at nearly 150k miles - it's due anyway. I'm curious to see if putting in the new ones makes any difference with anything. I know it's leaking gas internally and flooding slightly when turned off hot. Not much to cause that sort of thing other then leaking injectors or maybe the cold-start valve.

[WME]

A leaking cold start injector or a dirty sticking injector. About equal chances. When I replaced my old head I also did a HP cam and bored throttle body, so no real base line for MPG with the new injectors

[Maineah]

Know any one with an exhaust gas analyzer?

[Derek up North]

I used to own one of these:-

Somehow, over the decades, I lost it. (In more ways than one! Before anyone else says it.)

[5Toyota]

got to be old like me to remember those cars . and that is a very neat tool I did not know about that tool.

[5Toyota]

on my 88 4WD XTRA CAB which has way way more miles then my dolphin and I run mostly local use . I kept fowling the plugs and getting ruff idle iwent to one number hotter plug. and fixed the problem .Do you think your new head valve job could have raised the compression on old rings have you pulled the plugs and checked them.

[shibs]

Hey JD, can you smog it and see if it is really running rich or at min it will tell what is wrong with it.

I have the same problem with my 90 winni,

My plan of attack:

1. run with 2 cans of techron injector cleaner.

2. check cold idle or what ever it is called sensor.

3. check oxygen sensor.

[zero]

Hey JD, can you smog it and see if it is really running rich or at min it will tell what is wrong with it.

I have the same problem with my 90 winni,

My plan of attack:

1. run with 2 cans of techron injector cleaner.

2. check cold idle or what ever it is called sensor.

3. check oxygen sensor.

I've got no way to check the air/fuel ratio. If any of the senors were screwing up - it ought to show up in a "check engine light" code. A bad injector however, will not. Even if I had the equipment to check what is coming out the tailpipe . . . I'm not so sure it would tell the story. The oxygen-sensor is pretty much doing that now. The fuel injection system used in these older Toyotas has no way of knowing if the individual injectors or fuel delivery is correct or not. It (sensors and computer) only sees the average fuel/air ratio of all four cylinders mixed together. So if two were lean and two were rich, I doubt you'd be able to detect it. That cannot happen with a carburetor system, nor can it happen with throttle-body or sequential injection. But with this crude setup - it can. It kind of makes my head hurt trying to figure what happens when the computer detects a lean output and sends in more fuel. If this lean situation is from one plugged injector - then the other three just get sent more fuel in an effort to compensate. Kind of a poor system, seems to me. My 1979 Datsun had a fuel-injection system that worked the same way (early Bosch Jetronic). Seems by 1988, Toyota could of come up with something a little better?

[Maineah]

It was the hot lick when it was new with the rest were still using feed back carbs.It was a a Bosch design like most of the electronic FI systems in that time frame. The O2 sensor reads what comes out of the exhaust the system. You can read the O2 sensor it must be active the system is designed to go rich to lean back and forth and try to maintain a systolic mix as an average so the O2 sensor will read some where between 0 and 1 volt 1 volt being rich low voltage lean usually when they go toes up it is either very lazy or kind of stuck at one voltage. The biggest player in the 22RE mix control is the MAF (it can be tinkered). An injector can be supplying fuel by correct opening time but not be working efficiently it's spray pattern can be poor more like a stream instead of a mist. A exhaust gas check will tell you because even one screwed up injector will cause either high CO or high HC if the CO2 readings are high enough it probably doing what it is supposed to.

[zero]

It was the hot lick when it was new with the rest were still using feed back carbs.

My 1979 Datsun had the Bosch L-Jetronic half-charge-per-rev , air-flow-meter controlled system similar to my 1988 Toyota and it's nine years older. The system came out in 1974. Seems in fourteen years - some improvements might of evolved? GM was using throttle-body injection at the same time and in some ways - it's a simpler and better system (in my opinion). Reliable. Cheap replacement parts, etc. And no way can a few faulty injectors cause an engine inbalance. Seems the Asians are very slow and cautious when it comes to adopting new tech. My 1990 Subaru was the last vehicle legally sold in the USA with a carburetor (or at least so I've read).

[shibs]

JDE, definitely my 90 v6 is running rich, my buddy driving behind me complained to me about smelling gas.

what would be proper steps to diag the root cause without throwing parts at it?

[linda s]

JDE, definitely my 90 v6 is running rich, my buddy driving behind me complained to me about smelling gas.

what would be proper steps to diag the root cause without throwing parts at it?

Check for codes.

Linda S

[zero]

Yes, checking codes is the first thing to do. Problem is - what to do when there ARE no codes? I can't speak off-hand about a 1990 V6. On my 1988 four-banger - the computer and sensors have no way of knowing if some of the injectors are not working properly. Maybe a 1990 V6 is different but without studying the matter - I don't know. I've never owned or worked on the V6 you have. Newer cars/trucks like with the OBII system can sense how each cylinder is running. That did not come out until around 1994-96 in most US vehicles.

[mustrmrk]

JD - I'll be very interested in how your new injectors work out - I've been thinking about replacing mine, too.

Also, being a 22re newb, I'm on a big learning curve, but perhaps this might be of value.

When we were heading West through N. Dakota last month, we had a 25-30 mph head wind one day. Needless to say, we stopped early. When we filled up the next day, I was appalled that we'd only gotten 9.4 mpg. I didn't know you could even push that much fuel through the 22re engine! I believe the engine was "acting up" that day, but not badly and the headwind was masking the problem.

That was the most abysmal fuel mileage we've ever seen in the RV. However, on days when the engine is acting up (I suspect the connection to the MAF sensor) we'll see symptoms that vary from slightly lower power across the board leading to excess fuel use) to very low power at low rpms and plenty of power in the higher rpm range. I can't pin it all on the MAF sensor, however, as several other connectors (TPS, temperature sensors, etc.) are also old and missing their retaining clips. With that headwind, I was running in 3rd gear -no overdrive - with the pedal pretty much to the metal.

At any rate, I just replaced the MAF sensor pigtail and, once we get the motor back together this weekend, I'll be running diagnostics on the EFI. I would suggest also looking at your MAF and the other EFI electrical connections as possible contributors to your problem.

[mustrmrk]

Also - wouldn't an injector persistently running rich carbon up its spark plug enough to identify the problem injector?

[zero]

Also - wouldn't an injector persistently running rich carbon up its spark plug enough to identify the problem injector?

Yes, seems it ought to. I've never even had the plugs out of this engine since it got the head rebuild around 2000 miles ago. The mass air-flow is something you can check with an ohm-meter and verify if the variable resistor in there is working as it should. If it does not, it ought to throw and error code I already checked my air-flow "pot", and also did a resistance check on my throttle position sensor (another variable resistor).

If the variable resistor is bad in the mass-air-flow box - I'm sure what is to be done about it. I don't know if just that variable resistor can be bought or not. I DO have a spare here. I scrapped a 1987 box truck with the 22RE and have the entire engine here for parts.

The throttle position sensor can be bought new for $45.

In my case, there are no error codes. That's why I suspect the injectors. I got my brand new injectors yesterday. They are "Standard" brand but are actually genuine Denso injectors which is a nice surprise.

It's raining today so maybe I'll work on my Toyota. I kind of dread it. I took a look in there and changing those injectors is not exactly simple. Lots of stuff in the way.

[shibs]

hey JDE, before you pull those injectors, maybe you can add some chevron techron to the gas and drive around and see if that makes a diff.

I had good luck with techron cleaning up clogged injectors in other vehicles.

most of my vehicles are not driven for 6 months to a year.

[zero]

Not my way of doing things. Injectors have wear issues other then being dirty. This engine has around 145,000 miles on it as far as I can tell. At this point, even if an injector WAS dirty - I'd want a new one anyway. But it has good power and runs smooth so I doubt any are plugged. I think they are leaking and letting gas through when not turned "on."

I don't pretend to know a lot about these little solenoid-activated injectors. THIS I do know. They are pintle injectors just as the injectors are in my Ford 7.3 diesel. Pintle uses two pieces of metal that hammer away at each other and wear out. I see all sorts of ads for "rebuilt' gas engine injectors but see nothing about renewing the metal-to-metal parts. Just new o-rings, cleaning, and flow testing. In a diesel the metal parts get thrown away and brand new ones screwed on (pintle nozzle tips). No way to do that with a gas injector. Only way that I am aware of - to restore full service life - is to buy a brand new (not "rebuilt") injector.

I just put brand new injectors in this morning. Engine sounds find - but it did with the old injectors too. I won't know if I've gained anything until I get it good and hot and see if it floods anymore after shut-down. Or see if my trip MPG average goes up.

I DID discover one thing. I got done (so I thought) this morning and cranked the engine. NO start. Found out I left a ground cable off that fastens to the air-intake-manifold lower stud and nut. I am kind of amazed that by just leaving that cable off the engine would not start. Guess it must be the only ground (battery negative) for the injectors?

Here's what the new $80 each injectors look like from NAPA. I hated to spend the money since they are around for half that price, brand new if a person can wait. I need to use my RV in a few days and could NOT wait any longer. The new OEM Denso injectors I first bought for 1988 model-year only 22REs would not fit. Seems using model year is a bad way to sell parts. The seller should be using production dates. This 1988 was built in March of 1987. Seems all the non-turbo injectors are the same until 1988 production -and then go through many changes.

There are many places selling so-called "upgrade" four-hole injectors that require wiring changes to use. Not for me. I don't believe the claims of any increased performance from them. A properly working one-hole pintle injector makes a nice fine spray as it is. Up though 1987 -they are one-hole OEM. In 1988 - two -hole. After that - I do not know.

[shibs]

Good info, thanks,

these guys are near you for cleaning and testing, do ya mind sending the old injectors to them for testing :-)

http://cruzinperformance.com/

[zero]

So it looks like $19 per injector plus shipping (plus down time) to have them serviced. No renewal of metal parts. What would be the point? If I had time and was shopping carefully - I could buy brand new injectors for $25 each - outright, i.e. no exhange.

Even if someone was just doing routine maintenance - if the injectors have 120K miles and still test okay - they certainly don't have anywhere near the service life of a new injector. Neither do the so-called "rebuilt" Injectors. In my opinion, you'd still be way ahead to get new injectors and avoid down-time later. When I worked as a diesel engine rebuilder - part of our policy was new injectors with every engine tear down. That or brand new nozzle tips on old injectors when available. Some injectors are made in a way that all the moving parts can be replaced with new - cheaply. Brand new Bosch injector nozzles for my Ford diesel can be found for less then $10 each. Sometimes less then $5 each. But other injectors used in diesels and gas engines are more-or-less "throw-away" units (or at least, that is what we called them). They could be cleaned up, calibration checked, new seals put on - but when done they still had just as much metal wear on them as when we started.

Just my one person's opinion. If I wanted a engine that had the promise (or hope) of the power and future life of a new engine - I'd buy rebuilt. That "rebuilt" would mean virtually every metal moving part subject to wear has been checked and/or renewed in some way. Crank and rod journals and bearings, oil pump. cylinder walls, pistons, rings, valves. valve guides, valve seats, etc. I've seen many engines with over 200K miles that ran perfect. If someone cleaned one up though and put new gaskets in it - and nothing else - would anyone here accept it as a "rebuilt" engine? I hope not.

I see injectors and injector pumps the same way. The gas injectors have steel pintle nozzles similar to what my Ford diesel has. At least as far as I can tell . No process to renew those metal parts. Just a cleaning process to remove possible deposits.

[mustrmrk]

My issue with the MAF sensor was not internal to the MAF - it tests out as healthy using this protocol: http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

As I suspected, my issue was with the actual electrical connection between the harness connector and the MAF. The old connector had no retaining clip and the spring tension on the individual wire connectors was nearly non-existent. I ordered a new connector ($20 on eBay), cut wires to remove the old connector, and soldered and shrink wrapped each individual wire from the new pigtail back into the harness.

Before the repair I had intermittent and variable power loss and associated poor mpg. Now it runs reliably and efficiently.

[zero]

The old connector had no retaining clip and the spring tension on the individual wire connectors was nearly non-existent.

Seems those spring-clips get lost over time. I found three of them missing on my 1988. Just lucky to have a complete extra 22RE laying around that I robbed those clips off of.

I had a real bad go-around a few weeks ago with the auto-trans on my 1994 Ford F250. One morning - I started it up and only had 3rd and 4th gear. No 1st or 4th and no converter lockup. I spent many days trying to figure out what had happened seemingly overnight. Long-story short - it was the wire-harness connector on the trans. The lock was likely missing for a long time and it had probably been loose for a long time. Ended up cutting it off and buying a new one and like you - installed with butt-connectors and heat-shrink tubing. Runs like new now.