1988 911 won't

ztobaja · 07-03-2021, 11:17 AM

1988 911 will not start, new battery, new pump and relay, gas through new filter to engine, has spark at plug wire removed, plug inserted. cranks but will not start.
pulsated then Quit on freeway AAA truck home

Joe Bob · Joe Bob's Garage

Is the CDI box whining?

ztobaja · 07-03-2021, 06:34 PM

Thanks, Bob will listen, when key in on position? or?
Also with fuel line removed from filter leading to the engine, gas comes out in a long steam, [ to a bucket of couse]

dkirk · dkirk's Garage

I have an '88 and had the same problem, except mine would not start in the garage (I was lucky). Spraying some starting fluid in the intake, the engine would run briefly, thus indicating that injectors were not functioning. What failed was the ECU - a conductive path on one of the circuit boards had open circuited. I sent the ECU to Steve Wong for reconditioning, repair and testing. Car has run perfectly ever since.

mysocal911 · 07-03-2021, 07:42 PM

Let Pelican Parts help you; 911 3.2 No-Start Troubleshooting

ztobaja · 07-03-2021, 08:38 PM

Bob, no CDI unit or any other component in rear inner fender panel, just delayed ignition cut-off relay. Bought the car from an east coast dealer. Had it two months then this

brighton911 · 07-04-2021, 04:17 AM

A faulty reference sensor or CHT can cause a no start. Use Search to find test procedures. Here is one example:

3.2 No Start but sensors check okay. Advice Requested

ischmitz · ischmitz's Garage

A stock 1988 uses a Bosch DME for fuel and spark. If you have spark the flywheel sensors are fine and it's either an issue with fuel pressure (lack thereof) or the part of the DME that controls the fuel injectors. For further diagnosis and narrowing it down here is what you can do:

1. Spray carb cleaner or brake cleaner, starter fluid or similar into the air filter inlet and crank. If the engine catches and runs for a brief moment this confirms spark is good and the flywheel sensors are fine and it's the lack of fuel.

2. Get yourself a set of NOID lights and test for fuel signals at the injectors. If they are present it points to fuel pressure (lack thereof) or clogged/stuck injectors. That is possible if the car sat for a long period of time. Other suspects are fuel pump, pressure regulator, fuel accumulator, etc. You might want to invest in a fuel pressure gauge set.

If there are no fuel pulses it's either a shorted injector (they are all wired in parallel, disconnect one at a time and retry) or the DME itself is bad.

Cheers,
Ingo