Guest bigjim240z Posted November 21, 2003 Share Posted November 21, 2003 i have a freind with a 1986 302 ford 5.0 motor in his 240z. its all stock with the efi. its been running well, but latley it wont idle well. some times the idle lopes, then some times it will idle. whats the deal with it. thanks for any help. Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted November 23, 2003 Share Posted November 23, 2003 man no one has any ideas? this ford section is slow compared to the chevy section! Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted November 23, 2003 Share Posted November 23, 2003 There are two reasons for the slow response to your query: First, there are far fewer member with Ford engines in their cars. Second, the 1986 5.0L fuel injection is an animal unto itself. It was the first year for the 5.0L to be fuel injected, and was noted to be problematic. The fuel injection system on the 5.0L was improved in 1987 with the introduction of the EEC-IV computer, and improved again in 1988 with the introduction of the Mass Air version of the EEC-IV. My suggestion would be to dump the 1986 fuel injection and update to the 1988-1993 version. Better yet, get an entire engine with the wiring harness and computer(1989 - 1991 preferably). These packages are plentiful and relatively cheap. THe 1986 engine had inferior heads, intake manifold, pistons with no valve reliefs, and other idiosyncracies that make it less desirable than the later engines. Good luck, Dan McGrath Quote Link to comment Share on other sites More sharing options...
Guest bigjim240z Posted November 23, 2003 Share Posted November 23, 2003 it would be a serious job to swap the whole harness and engine in his car, especially when nothing is wrong with it, well beisdes the idle. the motor has less than 70,000 miles on it and burns zero oil. and the car is pleanty fast so the heads and intake are fine. what i have to find out are common things that would cause this motor to idle irratic. it has no vaccume leaks, no bad hose's, the motor is freshly tuned and runs perfect except for the idle. before i would ever goto 87 and up efi i would just ripp everything off, install a single plane intake, motor sports f303 cam and a big ass carb. thats what my z is getting. efi is a pain to trouble shoot. Quote Link to comment Share on other sites More sharing options...
Guest buschj Posted November 24, 2003 Share Posted November 24, 2003 Idle air control valve. Remove it and clean all of the passages and see if it helps. Otherwise replace it. John Quote Link to comment Share on other sites More sharing options...
Guest kc280zx Posted January 18, 2004 Share Posted January 18, 2004 86 is speed density fuel injection 87-88 were only mass air in california, rest were speed density. 1989 was mass air. you have a speed density fuel injection system. your computer takes the atmosphere for granted by using a MAP sensor, unlike a MAF car, which meters the air as it comes in, the MAP sensor cars just assume it is taking in the same amount of air per revolution of the cam. They are great, because unlike what most people will tell you, they actually make more power than maf sensor cars. However, you cannot put cams or big upgrades on them because they will run like horse shit. I've seen a few people get away with it, but very far and between. If you want to get some VERY comprehensive information, you might want to register over at stangnet.com and ask in the 5.0 forums, the people that browse their forums have actually built their own ECU's and fuel injection systems, so they know their stuff. Quote Link to comment Share on other sites More sharing options...
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