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86 Runs for 15 secs then dies, smells rich.


stonetree
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A week ago my 86 conquest started hesitating off and on. I added some heet-no difference. Added some injector cleaner and it ran a lot better( almost back to 100%). No hesitation until yesterday, when it started doing it again and then Backfired! Barely ran after that and barely limped the last 4 blocks home. Now it will start right up and run for 15 seconds then dies. Fuel pressure is around 35 psi same as always. Could a injector be bad, causing it to flood? Any ideas?
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I tried a set of Trilogy injectors a year ago trying to solve a bucking problem. The car would not even idle with them, I even reset the TPS twice trying to make them work. Trilogy let me return them after we confirmed the car is an 86. Somebody has swapped in a newer MAS, so that may be why they did'nt work for me. So I put the old injectors back in and it idled fine, until yesterday. I think the Trilogy injectors were good, just not good for my car.
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Unplug your CTS and also see if your plugs are fouled. A bad out of range CTS in cold or very cold weather can cause too much fuel in 83-86s and if you never did get those original injectors cleaned that's likely the problem they are just spraying so poorly it ends up flooded.
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Unplugged the CTS and it won't start. Plugged back in, it starts and runs for about 15 seconds. I bought a MAS from an 86. But I don't have the right pigtail for it since someone swapped in the newer MAS and pigtail in my car.
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I did'nt do anything to the MAS. The reason I know its different from stock is I bought a stock 86 air can that came with a stock 86 MAS. Also the 86 manual showed a different pin setup. However your probably right about that being a problem area.
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I unplugged what I think is the MAP sensor and now it will idle(barely)but it does'nt die, awesome. It has 3 vacum lines and 2 male spade terminals. It's located near the firewall and one of the vacum hoses runs from it to a box mounted on the firewall. You guys are great, thanks. Now how much does a MAP sensor cost and are they still available?
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Yikes, you have two options. Make a wanted ad for a working map sensor, or convert to an 87-89 engine harness and ecu. Or it might be a combination of things not working that caused the problem. I think you should try the first option, but inspect the whole system and tune it up if you need to. Good luck. Also, there are some people here who know all about the 86 electronics, so don't hesitate to ask.
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I unplugged what I think is the MAP sensor and now it will idle(barely)but it does'nt die, awesome. It has 3 vacum lines and 2 male spade terminals. It's located near the firewall and one of the vacum hoses runs from it to a box mounted on the firewall. You guys are great, thanks. Now how much does a MAP sensor cost and are they still available?

 

That's not the MAP sensor, that's the barometric sensor. Also, unplugging the real MAP sensor will do nothing for the car but force it into limp mode and it will not want to drive anywhere.

 

You need to get your stock MAS wired up (I'm guessing someone put a 1g MAS on your car). Ensure your injector clips and terminals are clean and secure. Yes, you should do a TPS/ISC reset. Here is the correct procedure for an 86: http://www.starquestclub.com/forum/index.php?showtopic=27979

 

How well does it run for those 15 seconds?? Does it rev smoothly, or does it barely want to run?? What is the engine idling at for those 15 seconds?? Can you restart it immediately after it dies??

 

Have you inspected your spark plugs and plug wires??

 

-Robert

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  • 1 month later...
Finally got the quest inside where I can work on it. Runs like crap for 15 seconds then dies. Smells rich. Checked plugwires (5 months old) visually, same with plugs all look undamaged. Swapped TPS made no difference. Checked resistance on injectors and that resistor "thingy" mounted behind the passenger headlight, all 0 ohms. The manual says to replace all, but my injectors always have measured 0 ohms even when it ran good. I have a spare throttle body and the injectors on it measure 0 ohms also. Plugged a noid light into injector connectors, barely lit up and was steady with hardly any flash or pulse visible. Thinking about swapping injectors with the ones on the sprare 86 throttle body. Any ideas?
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Checked resistance on injectors and that resistor "thingy" mounted behind the passenger headlight, all 0 ohms. The manual says to replace all, but my injectors always have measured 0 ohms even when it ran good. I have a spare throttle body and the injectors on it measure 0 ohms also.

 

If they are at 0 ohms, you've got a unsual and serious problem. Are you SURE!!! Maybe change scale on your voltmeter?

Verify your voltmemeter on a known value resister.

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I was thinking the same thing so I changed the values and came up with the same results. Next I used another meter and still got the same reults. Either I am really bad at using these meters or I got bigger problems. Great minds think alike. :)
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The OVCP, is there a sensor in it? If there is don't plug it in because that's why the MAF was changed. The MAF for your car has a round plug. That is the "map" sensor on the firewall or you can call it a pressure sensor. There's a vacuum hose to it from the throttlebody then in that line is a solenoid to sample atmospheric pressure every couple minutes from inside the air filter can. That can't be hooked up wrong or not connected at all. You said it starts if you hold the throttleopen, its because it needs more AIR because those injectors are spraying in too much and poorly. Take them out and have them cleaned. Why? One dirty injector in an 87-89 can cause a car to not start and its almost half the size of the TWO you have that likely are both dirty. They don't fire any quicker than the 87+ fuel system does while cranking but they still can flood the motor. The plugs will be fouled, and are now and eventually it won't start at all. That CTS, leave it unplugged its just making it worse by added in even more fuel when its cold. Moving the throttle and causing the TPS to change while cranking won't do anything all you are doing is letting in AIR to dilute the fuel that you have too much of.

 

There's another possible reason it won't start too. You ignitor is dying. Don't overlooked those injectors needing to be cleaned or those spark plugs. Your engine came with a BUR6EA-11 plug, you can get a one step colder plug, BUR7EA-11 but you'll have to order it, they cost no more than the "alternate" plug and while you are having this too rich issue that's one of the reasons why they used it. You can order them by that long part # or just 7031. The difference from this to a BPR7ES-11 is that the tip is enclosed to prevent them from fouling. The air fuel ratio on these cars spikes HIGH and LOW, you see this on those air fuel gauges as you drive the car, this plug doesn't much care about that. Other plugs do and some won't work at all. Its not the heat range, material or brand its just the tip design.

 

http://www.b2600turbo.com/images/semisurface2.jpg

 

http://photos-e.ak.fbcdn.net/hphotos-ak-snc1/hs123.snc1/5289_1027208978663_1778479606_56212_606787_n.jpg

 

 

 

http://www.b2600turbo.com/images/86vachoses01.jpg

 

http://www.b2600turbo.com/images/86vachoses02.jpg

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Is the igniter the same thing as the coil, do you have a part # or picture of it? Also I don't have a sensor in my aftermarket OVCP. Could that be a problem? It ran good without one and I don't see a place to mount one. Is there a way to test the MAP?
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