SPFI EA82 Hesitation on Acceleration when Cold

[JEBalles]

My '89 GL Wagon with the SPFI EA82 seems to struggle a little on acceleration when the engine is cold. It also is harder to start when cold, 1-2 sec. of cranking vs. immediate start when warm. That doesn't bother me, but could be connected.

 

If I accelerate slowly, it's fine. At speed it's fine. When warm, runs great.

 

If I try to romp on it at all when it's cold, it hesitates and bucks. So far, I've disconnected the EGR, cleaned the MAF, fixed the timing and replaced the plugs. My next target is the coolant thermosensor. Wires look fine, I cleaned the connections with electronic connection cleaner. I'll try it tomorrow to see if that did anything, but I doubt it.

 

Any ideas? Replace the sensor next? I plan on testing the resistance next week.

[The FNG]

You could try cleaning the MAF, but I don't assume that is the issue. Did you check the plug wires when you replaced the plugs? How about the distributor cap or rotor for corrosion? I had an issue with corrosion in my coil at one point too...Check the air filter??? Hopefully someone can give you more precise judgement on the situation.

[FlatFourFrenchy]

My 94 does the same exact thing. Kinda just thought it was the nature of the beast. I know carburater cars have done this for years when the choke was a little off so that would lead me to guess that it ia a fuel delivery issue. Never really bothered me for the two minutes it lasts if I don't let my car warm up good.

[mikaleda]

sounds like the coolant temp sensor that is common problem on all makes of SPFI. my dads s10 blazer did this we were going to buy a $120 egr but the guy at napa said to try the coolant temp sensor and it fixed it. i think what happens is the temp sensor malfunctions and gives the computer the a warmed up temp so its not adjusting the amount of fuel to give it. there is no choke on a spfi it just gives more gas

[JEBalles]

Well, I checked the resistance for the coolant thermosensor: in spec. How do I check the wires and distributor cap? And I guess I'm just gonna replace the air and fuel filter for good measure.

[Subruise]

what brand plug wires are you using? l series cars MUST have ngks. if not, prepare for suck. speaking of which, got any vac leaks??

[JEBalles]

I'm not sure about the wires. I couldn't find anything identifying on them and they look fine to me. I don't know what a bad spark plug wire looks like though. And how do I measure if I have a vacuum leak? Do I just hook up a vacuum gauge to any vacuum line?

[JEBalles]

Another update: after checking the resistance of the termosensor (including wiping on the actual sensor and cleaning the electrical contacts), it's started behaving more or less how it should. Could this just have been a case of dirty contacts??

[mikaleda]

could be :cool:

[psylosyfer]

I had similar problem hard to start, very bad when cold, after going round and round, turned out to be plug wires, I had a spark at the plugs but I guess it was to weak. New wires, fired right up.