UK Chris

Hi Guys. I live in the Uk and have owned my 1991 RS 3.1 for 13 years. It has developed a fault that I just can’t seem to get to grips with. So I am hoping that you guys with your unique product knowledge will be able to put me on the right track. It would run perfectly for a few miles then just stop. It would not restart, when left to cool it restarted fine and ran well for another few miles. This turned out to be the pick up coil in the distributor. Rebuilt distributor (Cardone Industries) fitted, base plate timing set at 10 degrees as per the book. Sadly the car had to go in the garage for three years. I got it out this year, fitted a new battery and it started first turn of the key, But it now seems to stutter like it is missing and worse when it is under power, hills etc. At first I thought that it was old fuel, but no. The parts I have now changed are. New fuel filter, lambda sensor, EGR valve, map sensor, plugs and wires, coil, cap and rotor. I have done a smoke test and there appears to be no vacuum leaks and now no leaks in the exhaust. It idles very fast and the rev counter is reading much faster than the engine is running (always done this) It is running better when you first start, as it get warmer it reverts back to lack of power and missing. Your thoughts and advice would be much appreciated. Chris.

me420

Does it have fuel injectors? If so check them

Base91

iTrader: (1)

Welcome to TGO. Try to get at least a Chilton's manual for the car. It has lots of explanations and diagnostic tips. As said, check the injectors. If the are original )or even old) they almost certainly need to be replaced. You need to take off the upper plenum to get to the injectors. Measure the resistance of each. Should all be about 12+ ohms and all very close in value. Also, as you'll have the right parts off it would be a good time to replace the diaphragm in the fuel pressure regulator. If you need new injectors Southbay on this board do a good set for less than $130. Don't know about the cost of shipping to UK. With known good injectors and fpr you can start fixing any other existing issues. Also a good idea (among others) to remove and clean the idle air control valve (iac) and the passages in the throttle body. Once mine was running ok I started running Seafoam in the gas for a while and it made a huge difference.

Base91

iTrader: (1)

BTW where in London are you?

UK Chris

Base 91. Thank you for your good advice. I will start pulling her apart next weekend. and put new injectors and fuel pressure regulator diaphragm in. May I ask, what is Seafoam????? I buy most off my parts from Ebay USA. The parts are very reasonable it,s just the shipping and duty that is a little expensive, but still cheaper than buying in the UK. I live about 40 miles south of London in a small village called Harrietsham. Yours Chris.

Base91

iTrader: (1)

Seafoam is a cleaner. You can put it in the tank and it'll help clean out the engine if it hasn't been rebuilt any time recently. There are other similar products but I had great results with the Seafoam. My engine wouldn't run above about 3k rpm. After Seafoam in a few tankfuls of gas it runs easily up to at least 5.5k rpm with some left.

southbay08

Hi Chris, welcome to tgo! Members are great and have a wealth of knowlegde. As mentioned above check the resistance on your injectors, but check them when they are hot. The older style injectors are very prone to coil failure, however it will not rear it's ugly face until the engine warms up and the injectors are hot. That is when they begin to shut down/fail.

www.southbayfuelinjectors.com
516-442-4707

me420

A good trick to clean out engine gunk i used for my Z is 4 new quarts of oil and 1 quart kerosene. Let my car idle 15-20mins. Then change oil, let it drain well. Kerosene acts as a detergent but dont run it too long. I forget how much came out first but the next time i changed the oil(months later) my oil filter was filled to the brim with sludge. Success!! ??

The intake gasket was draining antifeeze in my oil. So as i took my top end apart it was filled with a mayonaise substance from antifreeze and oil mixing. I cleaned the topend and got the valves done. Before driving the car is when i did the kerosene clean trick. Wondered if any was left in the block, oil pan, or the oil pickup line.
Less than a year later to my relief while eventually installing new main bearings(haha) i had the luxury of taking my oil pan off and see how well it cleaned. Everything was spotless. Not a spec of sludge in the pan or on the oil pickup screen, which at the time was actualy bad news for my no oil pressure diagnosis. Lol

UK Chris

Thank you all for your comments and advice. A little more information, Last weekend I took the car for a 500 mile trip, yes it was not running right but the “Service engine soon” light never came on once. On my return I removed all the plugs. They were all burning identically, I gave it a compression test (the engine was cold) and 5 cylinders gave 170psi and 1 cylinder gave 160psi, I think this is OK but please let me know if it is not. This leads me to believe that the problem is common to all the plugs or injectors, because if 1 or 2 plugs or injectors were breaking down it would have shown itself in that the plugs would not be burning identically. I want to now test the pump pressure, as I am thinking it is a fuel problem but am not sure what it should be. Can you please help? Thanks for your time. Chris…… I WILL GET HER RUNNING RIGHT!!!

Base91

iTrader: (1)

Unfortunately not so on the injectors. One or two can be performing poorly and the engine will still run. The ecm will try to compensate. However, on these engine 1 bad injector can shut the whole thing down. I originally have resistance measurements ranging from about 3 ohms up to 12 and it still ran but fuel consumption and performance were terrible. Then one injector died completely and no start. With replacement injectors it ran fine until one died after 2 months. Again no start. I replaced the one injector and it was fine but I didn't trust the injectors so got the set from Southbay and keep the others as back ups. As for fuel pressure I think when you turn the key on but not start it should be about 40 psi or so and hold pressure for a decent length of time. Some say hours but mine isn't that good. The pressure should climb slightly as revs increase. As the car is still running you could run some Seafoam in the gas and get some cleaning started until you replace the injectors and fpr diaphragm.

UK Chris

You cannot buy Seafoam in Europe, not sure why. Good old Ebay to the rescue! 1 can on it's way!!!! I will start getting all the parts together. I am hoping that Southbay will ship to the UK, Will be getting hold of them soon. So again I thank you all for your help, and a special thank you to Base91, your help and advice has been invaluable. I will report back later to let you know how things are progressing. Chris.

UK Chris

New injectors and diaphragm fitted. No difference!!! But I have had a thought. before all this trouble the heater core leaked.. Steam and water came into the cabin, as the core and the ECM are close maybe water has got in the ECM and fried it. I have got a new ECM (Cardone) but I think that I want to replace the prom at the same time. I can find new proms on Ebay but they are all for auto boxes, mine is manual. Are they the same? When fitting the ECM (with battery disconnected) Do I just replace it, reconnect the battery and start the engine back up, or do I need to do anything else before starting the engine? Thanks. Chris

vetteoz

iTrader: (13)

Have you pulled the engine fault codes to see if anything showing ?

https://www.thirdgen.org/forums/tech...s-dumbies.html

UK Chris

Hi vetteoz All the time I have had this problem the engine service soon light has never come on, I have pulled the codes and the only code that came up was for the EGR valve, This was replaced with a new one. The ECM is now not showing any faults at all. Cheers, Chris.