Driving home the other night my car just suddenly died on me just before a set of traffic lights & in everyone's way. I tried to restart it & after a couple of attempts it fired up but died again as I went to pull away. I spent all yesterday trying to get it running but nothing. This morning I have replaced 3 ht leads which were giving no resistance reading, obviously broken down, put old spark plugs back in, cleaned the distributor cap & rotor arm & the engine fired up from cold no problem Within a few minutes it started to misfire & eventually died. If I leave it a few minutes it will start but runs lumpy & then dies. I have replaced the coil & amplifier,ECU, MAF & checked to make sure fuel is flowing, when the engine ran it filled a 2l milk bottle in seconds so not a fuel problem. It is an electrical fault somewhere as when something gets warm it is breaking down. I am starting to run short of hair can anyone help please.

 

Sorry your having this problem with the car, I had something similar with my Jag. I know you don't think its fuel, but with mine it was a plugged fuel filter.

 

Hi geridiver,

My first reaction to your symptoms is that you may have multiple issues that are causing a "perfect storm." As R-rocks has already mentioned, the fuel filter would be one of the first things to replace just to rule it out. Is it possible that at your last fill-up you got some bad petrol that contained water?

A typical contributor to hard starting at all times and vapor lock when the engine is hot is a failing Fuel Pressure Regulator (FPR). If it is no longer holding proper pressure in the fuel rail (approx. 40 psi), the engine can be easily starved as the revs rise. And when you shut off the hot engine, the immediate loss of pressure causes the fuel in the rail to boil into gas, creating classic vapor lock, and the engine won't start again until the fuel condenses back into liquid. FPRs are not too expensive, so if you're still running your original one I would recommend replacing it as a matter of course. It's actually cheaper to replace the FPR than it is to build a rig for testing the fuel pressure with a gauge. One test you can perform on the FPR is to remove the vacuum hose from the fitting on the FPR and watch the fitting while someone cranks the engine. If you see any fuel at the fitting, the diaphragm has failed and raw unmetered fuel is being inhaled into the intake manifold causing rich running. Below is a link to photos showing how I replaced the FPR on our '93:

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You might try replacing the Fuel Pump Relay, especially if you're still on the original one. They don't last forever, and their operation can become intermittent as they age. Check also for corrosion in the socket base for the relay. Off the top of my head I can't remember where the relay is on an '88, but if no one else chimes in I know it's shown in the Haynes manual, which can be downloaded from this forum.

The oxygen sensor takes 20 seconds or more to reach operating temperature, so the ECM is programmed to ignore it for a predetermined amount of time and instead to apply cold start fuel enrichment by lengthening the fuel injector pulse duration. If the O2 sensor is not operating properly, when the ECM goes into closed-loop fuel metering and doesn't receive a correct signal from the sensor it may continue the cold start fuel enrichment, leading to poor running.

Check your transmission fluid to be sure it's right at the HOT mark when the transmission is hot from a good drive and that the fluid is bright red and has no burnt smell. Believe it or not, low (or overly full) transmission fluid is associated with engine stalling, especially after a stop or when turning.

If you don't know the age of your Crankshaft Position Sensor (CPS), I would strongly recommend replacing it preemptively and keeping the old one in your trunk as a spare. As they begin to fail, they can cause hard-to-diagnose starting and stalling issues.

It would also be worth cleaning the grounds, especially those in your engine compartment. Below is a link to photos of the grounds on our '93 and how I service them. To see other grounds just click on the My Photo Albums button:

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It's late so I'm having trouble thinking clearly, but those are some things I'd check first.

Cheers,

Don

 

Thanks for the replies. I forgot to mention my car is petrol or lpg & the problem is the same on both, so definitely not a fuel issue. There is no oxygen sensor on this model & I have replaced the cps.I have replaced the fuel relay just in case although the Haynes manual shows it in completely the wrong place, the fuel & main relays are under the others. I have checked the mass airflow sensor as per the haynes manual & on pin 6 I am only getting 2.4v instead of 5v, hoping that the manual is giving the correct test figures, which seems to indicate this is the problem. Replacing the MAF with a second hand one makes no difference so I am waiting for a new one to arrive. I will post again when I get it fitted.

 

The new MAF sensor made no difference. Eventually I could not get the car to start & was out of ideas until a friend showed me a neat trick. The spark @ the plugs was intermittent & weak so he took the coil/dist. cap lead out @ the distributor end, held it close to earth & cranking the engine produced a good spark. Removing the distributor cap, he held the lead close to the centre of the rotor arm. Cranking the engine produced a spark indicating the rotor arm insulation had broken down with the ht spark earthing down the distributor shaft. New rotor arm problem solved. This is one test you can't do by yourself.