MAP sensor connector problems.
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4wd Low
Joined: Apr 2025
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MAP sensor connector problems.
I kept reading these forums without creating an account to see if I could figure out what was wrong but doing so hasn’t given me any answers. My truck will not run for long when the MAP sensor (Electrical connection) is plugged in. It will start up sputter and then die. When I unplug it though, it runs fine but rough like you’d expect it to because of the unregulated air pressure. When I plug the electrical connection back in the truck immediately dies. I’m getting proper voltage to my MAP sensor. I’ve replaced my map sensor, and have gotten the same results. Any thoughts on what might be causing this?
For reference this is a 1993 F-250 with a 5.8l 351w and 199k original miles.
For reference this is a 1993 F-250 with a 5.8l 351w and 199k original miles.
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4wd Low
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No. I cannot. I followed a YouTube tutorial on how to get my check engine (pre-OBDII) light to give codes. I put a paper clip in the certain ports on the EEC test and the other gray connector to give the engine codes to the check engine light but the check engine light doesn’t flash. Also I don’t know if I have a PCM or ECM. All I know is that whenever I try to do a KOEO test the engine light doesn’t flash. The same goes for a KOER test as well.
Last edited by Wiill; Apr 22, 2025 at 08:46 PM.
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
OK. that also suggests a PCM problem. Question, does the CE light come on when the key is first turned to run before the engine is started? If it does then you know the bulb isn't burned out or missing.
PCM and ECM are two names for slightly different computer controllers, the former controls both engine and trans while the latter is just for the engine when a manual transmission is used. They look identical
PCM and ECM are two names for slightly different computer controllers, the former controls both engine and trans while the latter is just for the engine when a manual transmission is used. They look identical
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4wd Low
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Yes, the CE light works. I know the computer is at least trying to give me codes because when I go to start it, it comes on then goes off in a split second when the paper clip connector is in but does not go through the series of flashes to give me the codes. It just stays off. Also if what you said is the case then I have a PCM because my truck is an automatic.
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4wd Low
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New PCM in FT2F-12A650-PB which matches my old one. Truck is sluggish as crap in the throttle and won’t move on a slight incline. The breaks feel as if the truck was off. I think I need to program my PCM to my VIN but that might be the problem. Also it idles low as crap. I was able to pull a 327 code which I fixed and then I couldn’t pull anymore because my fuel pump relay blew and the fuel pump doesn’t turn off. That’s where it’s at since I last posted on this thread.
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
It easy to test the relay, just remove it from the truck and momentarally apply 12v to the coil pins, if it clicks it's OK. If the relay is good I'd suggest sending the PCM back as faulty and requesting another.
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Only if the transmission has overdrive. Since you have a 3/4T truck that limits which transmission you have to either the mechanical 3 speed (C6) or the Electronic 4speed Overdrive (E4OD).
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4wd Low
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My truck has the E40D with the overdrive. But ever since I put the new PCM in it’s had some sort of pressure or vacuum issue that’s causing my brakes not to function unless they’re in reverse, and my transmission not to shift and my engine not to rev under load unless it’s in reverse, and my fuel pump not to cut off either. And it only cranks off starting fluid but when it’s hot it cranks fine. The other thing I noticed is that whenever my hood is closed it idles low and when opened idles up. So just a bunch of weird stuff.
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My truck has the E40D with the overdrive. But ever since I put the new PCM in it’s had some sort of pressure or vacuum issue that’s causing my brakes not to function unless they’re in reverse, and my transmission not to shift and my engine not to rev under load unless it’s in reverse, and my fuel pump not to cut off either. And it only cranks off starting fluid but when it’s hot it cranks fine. The other thing I noticed is that whenever my hood is closed it idles low and when opened idles up. So just a bunch of weird stuff.
Your last sentence suggests that the hood is closing of the air inlet tube, which would choke the engine.
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