HELP!!! 1985 c4 issue
Team Owner
Joined: Jul 2004
Posts: 28,422
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From: Hartford WI
He can try to unplug the Mass Air Flow sensor, the car will not like that considering that is the sensor the computer uses to determine engine load, but if it runs consistently then that may be it.
A few weeks ago my 85 would start and run fine, but a minute after taking off down the road it would loose almost all its power. Trying to accelerate it would hesitate with some sputtering, but WOT it worked fine. The check engine light came on most of the time claiming MAF circuit High voltage and low voltage. It would idle just fine though.
I highly doubt that it is MAF if it idles misfires at idle. If you want to test if it is a MAF, "borrow" one from the parts store and use it to test the problem. Return the part if it is not fixed. You seem like you are describing a misfire, but I have had people wrongly describe problems to me. Which makes fixing the car harder when it is not doing what they describe. Honestly, it's due to non-mechanics not knowing the lingo of the mechanics.
Can confirm that your car will not throw a code for misfire. Though, as someone mention it may cause other code to be shown that are not the actual problem.
A few weeks ago my 85 would start and run fine, but a minute after taking off down the road it would loose almost all its power. Trying to accelerate it would hesitate with some sputtering, but WOT it worked fine. The check engine light came on most of the time claiming MAF circuit High voltage and low voltage. It would idle just fine though.
I highly doubt that it is MAF if it idles misfires at idle. If you want to test if it is a MAF, "borrow" one from the parts store and use it to test the problem. Return the part if it is not fixed. You seem like you are describing a misfire, but I have had people wrongly describe problems to me. Which makes fixing the car harder when it is not doing what they describe. Honestly, it's due to non-mechanics not knowing the lingo of the mechanics.
Can confirm that your car will not throw a code for misfire. Though, as someone mention it may cause other code to be shown that are not the actual problem.
I think if the car goes into WOT mode, it ignores the O2 sensor so not a full closed loop whereas in idle it does read the full range of sensors?
IDK. I know once installed it is your's unless you are really good and tight with the people. IDK if they even accept returns on electronics especially if they order them. Might be easier to borrow a known good one from someone nearby.
ECM isn't that sophisticated so unless it is out of the plausible range, it might not even throw a code or if it does, the code might be misleading. Kinda why I prefer a scanner.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
Our conclusion on the truck was that is able to pull just enough dirt past the filter that it will get dirty. Could also be that the burnoff system isn't working right. I was hesitant to suggest the brake cleaner cleaning, we use one that is zero residue, but I know some leave a film.
An oily K&N could do it, a friends F-Body blew black smoke out of the tailpipes after 'installing' a K&N. Needless to say, it was oily, and you could trace the oil all the way down into the intake.
Disconnecting the MAF is a good call though, the same F-Body in question ran better with it's MAF unplugged - I imagine that the burnoff + oil didn't treat the MAF very well. OP could give that a try and report back.
An oily K&N could do it, a friends F-Body blew black smoke out of the tailpipes after 'installing' a K&N. Needless to say, it was oily, and you could trace the oil all the way down into the intake.
Disconnecting the MAF is a good call though, the same F-Body in question ran better with it's MAF unplugged - I imagine that the burnoff + oil didn't treat the MAF very well. OP could give that a try and report back.
Yep. Some oil is good, obviously, more is better. Maybe next week I will soak mine overnight in a barrel of oil.
OTOH, I have seen them pretty wet from inside the bag.Don't know but most people have been saying that they cured that problem with a new MAF.
Racer
Joined: Apr 2018
Posts: 349
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I don't have a MAF so IDK but IIRC, if it isn't working right and you suspect the MAF, disconnect it and it will run better if it is the MAF since the sensor will feed the ECM false info if it is connected. Disconnected, the ECM goes off stock tables which isn't optimum but better than the MAF saying it has 20 units of air when it only has 5.
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Joined: Feb 2018
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I don't have a MAF so IDK but IIRC, if it isn't working right and you suspect the MAF, disconnect it and it will run better if it is the MAF since the sensor will feed the ECM false info if it is connected. Disconnected, the ECM goes off stock tables which isn't optimum but better than the MAF saying it has 20 units of air when it only has 5. Or so I remember. Someone tell me if that isn't so.
I think if the car goes into WOT mode, it ignores the O2 sensor so not a full closed loop whereas in idle it does read the full range of sensors?
IDK. I know once installed it is your's unless you are really good and tight with the people. IDK if they even accept returns on electronics especially if they order them. Might be easier to borrow a known good one from someone nearby.
ECM isn't that sophisticated so unless it is out of the plausible range, it might not even throw a code or if it does, the code might be misleading. Kinda why I prefer a scanner.
I think if the car goes into WOT mode, it ignores the O2 sensor so not a full closed loop whereas in idle it does read the full range of sensors?
IDK. I know once installed it is your's unless you are really good and tight with the people. IDK if they even accept returns on electronics especially if they order them. Might be easier to borrow a known good one from someone nearby.
ECM isn't that sophisticated so unless it is out of the plausible range, it might not even throw a code or if it does, the code might be misleading. Kinda why I prefer a scanner.
You can return a part to the parts store and claim it is new and unused. If one plans to do it, keep the box and part as clean as possible. It may take a day or two for a store to get a MAF, but it should not be a special order item. They will probably have to get it from a warehouse. If it was a direct order item from the manufacturer then they may not take it back. My new MAF, not remanufactured, came in a sealed plastic bag. if the bag were to be open they may not take it back. I do know everyone at my local Oreilly's, so they were definitely taking it back no questions asked.
Easiest thing to do is unplug it and see how it does.
Racer
Joined: Apr 2018
Posts: 349
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Lol, it doesn't make much sense, but somehow the thing gets dirty, and brake cleaner fixes it. Even after a new air filter, still happens. It'll start hesitating, and after a clean, fixed. It's been ~10k miles since it happened, and only happened once since the new filter, where the old one was 3-5k miles. Freaking Ford, I guess.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
The MAF will though a code if the number reading does not correspond with the reading of other sensors and tables. Hints the reason the codes for a bad MAF is either circuit low and circuit high. the the MAF was reading 20 but supposed to be 5 that would be a circuit high code. I did watch the readings with a scanner, but it didn't do much good with an intermittent problem, and not knowing what it is supposed to read at certain times. BUT still, I find it HARD to believe a MAF is causing issues similar to a misfire.
You can return a part to the parts store and claim it is new and unused. If one plans to do it, keep the box and part as clean as possible. It may take a day or two for a store to get a MAF, but it should not be a special order item. They will probably have to get it from a warehouse. If it was a direct order item from the manufacturer then they may not take it back. My new MAF, not remanufactured, came in a sealed plastic bag. if the bag were to be open they may not take it back. I do know everyone at my local Oreilly's, so they were definitely taking it back no questions asked.
Easiest thing to do is unplug it and see how it does.
You can return a part to the parts store and claim it is new and unused. If one plans to do it, keep the box and part as clean as possible. It may take a day or two for a store to get a MAF, but it should not be a special order item. They will probably have to get it from a warehouse. If it was a direct order item from the manufacturer then they may not take it back. My new MAF, not remanufactured, came in a sealed plastic bag. if the bag were to be open they may not take it back. I do know everyone at my local Oreilly's, so they were definitely taking it back no questions asked.
Easiest thing to do is unplug it and see how it does.
I know that one but I haven't had the guts to pull it since those situations were minor. I'm saving it for when I have to. I don't like those stunts since it would be throwing my friends under the bus if there was an issue. Bring it somewhere else, act stupid and do it there. You don't want to do it to your friends. I know if you did it to me, I sure as hell won't ever help you so if you must, make it a good one since it is the last time. OTOH, you don't know the guy? Oh well. Nothing to lose.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
Lol, it doesn't make much sense, but somehow the thing gets dirty, and brake cleaner fixes it. Even after a new air filter, still happens. It'll start hesitating, and after a clean, fixed. It's been ~10k miles since it happened, and only happened once since the new filter, where the old one was 3-5k miles. Freaking Ford, I guess.
Racer
Joined: Apr 2018
Posts: 349
Likes: 55
My favorite is: "F-ed Over Rebuilt Dodge". Gets em both in one swing.
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Joined: Feb 2018
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For all you know, it might be the MAF AND another sensor.
I know that one but I haven't had the guts to pull it since those situations were minor. I'm saving it for when I have to. I don't like those stunts since it would be throwing my friends under the bus if there was an issue. Bring it somewhere else, act stupid and do it there. You don't want to do it to your friends. I know if you did it to me, I sure as hell won't ever help you so if you must, make it a good one since it is the last time. OTOH, you don't know the guy? Oh well. Nothing to lose.
I know that one but I haven't had the guts to pull it since those situations were minor. I'm saving it for when I have to. I don't like those stunts since it would be throwing my friends under the bus if there was an issue. Bring it somewhere else, act stupid and do it there. You don't want to do it to your friends. I know if you did it to me, I sure as hell won't ever help you so if you must, make it a good one since it is the last time. OTOH, you don't know the guy? Oh well. Nothing to lose.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
Sounds like Cabela's. Their return policy is crazy. You can buy boots, go hunting and return them. Look in the bargain cave sometimes.
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 15
Likes: 0
Good news guys... took everyones tips and tricks and just figured I would start with the cheapest thing... plugs and wires. everything was looking good til I got to plug number 8 and it was encapsulated in crap... back running 100 percent thank you to all who commented