Hello everyone. I am from South Africa and I have a problem. It is a bit long but I wanted to be detailed in order to provide the most information.
I run a small one man shop and I need your help.
A 1993, AE92 4A-FE (big intake body), manual transmission was towed to me as a non runner with a wiring problem. It had burnt wires from the distributor and a trace in the ecu... I repaired all of that and managed to start the car. The cause appears to have been from the distributor (probably a shorted capacitor... I found it melted).
I found out that the previous mechanics had blocked off the IACV air port in the throttle body, this caused the stalling when cold. One has to hold the throttle until the engine is slightly warm to maintain idle.
Timed the distributor and shorted pin TE1 and E1 and verified 10°BTDC and 15-17° when the pins are removed. Since they messed with the ICV, I cannot get idle to be at 900rpm... it stalls when I try to adjust it by turning the screw. By the way, I checked compression and it is a solid 120psi in all cylinders.
Here are my problems, I can smell gas coming from the tail pipe but the plugs seem to be normal. No leaks on the fuel rail, no leaks from injector seals... the customer told me that the car had overheated and a mechanic replaced the head gasket but I don't know how well they did the job.
Here is the other problem, I took it out for a test drive and it pulled well on first gear. Upon slowing down in order to negotiate an obstacle on the road, it stalled. Cranked it up and did not start until I feathered the throttle and it idled. I think this is related to the smelly gas situation...???
Under load it pulls well but when the load is maintained, you feel a very distinct judder or what others call fish bite. You can tell that this very very slight judder is a cause for concern.
I checked the MAP sensor as per workshop manual and it passed (see photo). Coolant sensor is fine too. Throttle sensor is fine but the previous mecahnics moved it around, can it cause the rich condition? I think so.
I started the car yesterday and feathered the throttle as usual (since the idle control valve was blocked off) and to my surprise it only revved up to 2500rpm!!! I pressed the pedal all the way down and it refused to rev up. The tacho needle just bounces between 2000 and 2500rpm. When you turn the key off and and start and feather the gas pedal, it starts and revs fine and idles.
I believe that this odd behavior is behind the stalling problem and the fish bite under load. Is the ECU bad? Cam sensor? Injector?
Another thing the tail pipe is telling me that the car is running rich but when I removed the spark plugs, they seem to be normal. But I can confirm that the full consumption is slightly on the heavy side. Should I focus on lowering idle to 900 rpm and reset timing and adjust Throttle position sensor and take it from there or what guys?
Customer says the car was driving fine before the wires got burnt.
May you help guys.
Thank you in advanced timing
Mshibonium
