Engine Starts Normally, But Doesn't Run

[mountainmansteve]

Greetings Dolphin Masters:

The saga of my 1986 Dolphin Electronic Fuel Injection System continues with a new chapter. The feedback andealth of knowledge I receive from all of you is greatly appreciated and highly valued.

I turn the key on, hear the fuel pump running, the engine starts immediately and runs for ~2 seconds then quits. The fuel pump (my most recent problem) was checked by the mechanic that replaced it when I returned from my most recent road trip; system pressure is 40psi, so not likely the current problem.

I have started some preliminary troubleshooting with a multi-meter. I am using the excellent 1988 Repair Manual that I downloaded from Waiter (John Mc) and have gained a fair understanding of the EFI System from the outstanding technical documents posted to a previous topic be Ya Baby! (Maineah), whom I recall previously taught this EFI System for Bosch.

So far I have tested the following fuses No 1 Relay Block ( under the driver's side inside the cab) EFI, Engine, IGN, and STOP (pg 238 of the repair manual). And No 2 Relay Block (passenger side inside the engine compartment by the battery) AM1 40A and AM2 30A (pg 38 of the repair manual)

I also checked the voltage at the ECU +B--E1, 12.2V and BATT-E1, 12.2V

This is as far as I can go on what I know to this point. Please Help!

Regards,

Stephen

[mountainmansteve]

Decided to try to push the accelerator to try to keep my Dolphin running after the initial start-up today with some very interesting results. I was able to keep the engine running as long as I was quickly pumping thlw accelerator. Fortunately, I had the help a very knowledeable Local Deputy Sheriff to look under the hood while I was madly pumping the gas.

Initially Mike was thinking it was a vacuum problem, but quickly shifted his focus to the exhaust manifold when I told him that I discovered a missing bolt some time ago. The short version is that there is a significant blowout in the exhaust manifold gasket at the point closest to the firewall between the engine compartment and the driver's side of the cab.

Mike explained to me that the leak could be causing an incorrect reading by the oxygen sensor located downstream of the leaking gasket. I think that this oxygen sensor dictates to the rest of the engine how much fuel to dump to the injectors. Mike said that the engine was definitely running rich--that the leaky gasket could also be allowing oxygen-rich air to enter the exhaust stream.

So, my next step is to replace the exhaust manifold gasket, get new bolts and properly sequence and torque the bolts when tightening. I'll let you all know what change this effects in my next post. Most likely Friday as I don't yet know the availability of the parts I need. For those of you whom have viewed this topic, this is a good one to follow through to the end.......

Truly,

Stephen

[Bob C]

Is it possible that your fuel filter is restricting your gas flow? When you listen to the pump run, it would push enough gas through to the injectors but the pressure would fall off quickly when the injectors started to push fuel into the cylinders.

[mountainmansteve]

Hi Bob C:

A good suggestion on where to start, simple, easy, and not too expensive.

Thanks and Kudos to you!

I replaced the fuel filter about a year ago, it was not the problem I was having when it was replaced, but that is where my Ex-Mechanic started. This, of course, doesn't indicate that my fuel filter is not the problem.

A Brother Firefighter with tools and knowledge has agreed to help me change the blown exhaust manifold gasket. One of our local Toyota Dealerships has the gasket and missing stud in stock and will have the nut for the stud Friday morning. Not sure when Rob can help me with wrenching, yet, but I expect to have parts by Noon on Friday.

More soon, and thanks again for your response.

Truly,

Stephen

Truly,

Stephen