1990 2.9 map sensor?

[djunkie]

Does this thing have one? I've looked everywhere. Truck will barely even run then all of a sudden it will start running good but kinda sounds like it has a mis. Then all of a sudden it dies and won't start. Only codes I got were a 29 and a 67. Would a bad act sensor do this? I pulled it out and the thing is caked with carbon.

A little history. Recent tune, has new ign. module, IAC is about a year old. A month ago we had a heavy rain and I stopped at a gas station and filled the truck up. Ran fine for about 5 miles till I got to work. After work I got in the truck and its running terrible. Barely made it home. Thought I had bad gas so I drained the tank changed the fuel filter. Thats where I'm at currently and it still runs terrible.

 

[djunkie]

Well I put a fuel pressure gauge on it. Turn the key on and it went straight to 40 psi. Started it up and it dropped to 33psi at idle. All of a sudden it cleared up and starting running perfect. Gave it some gas and it revved up smooth and perfect. Decided to take it for a test drive. Made it to the end of my street fine. Then I turned right and it started missing and crapping out again. Didn't even make it around the block and it died on me. Barely got it started to make it home. Any chance it could have a bad ECM? I had an S-10 that did this same thing and it was a bad ECM.

 

[IMenriched]

Well I put a fuel pressure gauge on it. Turn the key on and it went straight to 40 psi. Started it up and it dropped to 33psi at idle. All of a sudden it cleared up and starting running perfect. Gave it some gas and it revved up smooth and perfect. Decided to take it for a test drive. Made it to the end of my street fine. Then I turned right and it started missing and crapping out again. Didn't even make it around the block and it died on me. Barely got it started to make it home. Any chance it could have a bad ECM? I had an S-10 that did this same thing and it was a bad ECM.

double check grounds... and connections & check for vacuum leaks.

there is a ground wire by the ECM inside the cab.

might be a relay that is beinging iffy too.

did you check the little vacuum port and hose that goes just behind the throttle plate for carbon build up too??

also the little vacuum line on the back side of the FPR (Fuel Pressure Regulator)...pull it off and see if fuel dribbles out of it....if so...the FPR is done.

as far as the MAP goes, it ussualy is mounted on the fire wall just off to the passanger side of the intake...but early versions have them on the passanger side fender

 

[djunkie]

double check grounds... and connections & check for vacuum leaks.

there is a ground wire by the ECM inside the cab.

might be a relay that is beinging iffy too.

did you check the little vacuum port and hose that goes just behind the throttle plate for carbon build up too??

also the little vacuum line on the back side of the FPR (Fuel Pressure Regulator)...pull it off and see if fuel dribbles out of it....if so...the FPR is done.

as far as the MAP goes, it ussualy is mounted on the fire wall just off to the passanger side of the intake...but early versions have them on the passanger side fender

Which relay do you mean? Intake is clean. I checked that. Although the Air temp sensor was nasty looking. Fuel pressure regulator is new. I replaced it a few moths ago and double checked it today.

As for the map sensor, I looked everywhere. I cannot find it.

 

[djunkie]

Did they make any 2.9's without a map sensor? Cause this thing does not have one.

 

[The Fox]

There should be a vacuum line that comes off the tree on the passenger side of the intake manifold between the IAC and the throttle body. There are 2 line on it, one goes to the air filter box, and the other goes the to MAP sensor. Might be a TPS, since you have a code for it, but I don't remember how to check it. Someone else will come along and fill in the blanks I have.
Nick

 

[djunkie]

There should be a vacuum line that comes off the tree on the passenger side of the intake manifold between the IAC and the throttle body. There are 2 line on it, one goes to the air filter box, and the other goes the to MAP sensor. Might be a TPS, since you have a code for it, but I don't remember how to check it. Someone else will come along and fill in the blanks I have.
Nick

That tree your talking about has one line running to the airbox and the other is capped.

 

[Psychopete]

Did they make any 2.9's without a map sensor? Cause this thing does not have one.

Yes, but they are not common. Does it have a mass air sensor between the air box and intake tube?

Did you happen to test the fuel pressure as it/while it was running rough?

You can test the ACT, if it's bad, replace it and rule it out as being the cause.

http://www.fordfuelinjection.com/?p=29

Check the voltage output versus the temp of the ambient air.

Pete

 

[djunkie]

Yes, but they are not common. Does it have a mass air sensor between the air box and intake tube?

Did you happen to test the fuel pressure as it/while it was running rough?

You can test the ACT, if it's bad, replace it and rule it out as being the cause.

http://www.fordfuelinjection.com/?p=29

Check the voltage output versus the temp of the ambient air.

Pete

I think I have one of the not common ones then. I tested the fuel pressure both static and running. Checks out perfect. No fluctuation at all when it is running good or bad.

 

[djunkie]

Well I think it is the injectors. I pulled them all and they were full of junk. Time to clean the rest of the fuel system and get new injectors. Anyone know a good vender to get them from?

 

[djunkie]

Well I cleaned the whole fuel system. Put some new injectors in and it runs as good as new. Glad to have my beater back.

 

[IMenriched]

Well I cleaned the whole fuel system. Put some new injectors in and it runs as good as new. Glad to have my beater back.

glad to see your running good again

 

[Cees Klumper]

Reviving an older thread to confirm the answer to the original question, that it is likely some/many '90 2.9 V6 engines did not come with a MAP sensor, if they have a MAF sensor. Mine has a MAF and I can't find a MAP anywhere (although all the parts stores do carry one for my year and model).

 

[1986RangerXL]

Reviving an older thread to confirm the answer to the original question, that it is likely some/many '90 2.9 V6 engines did not come with a MAP sensor, if they have a MAF sensor. Mine has a MAF and I can't find a MAP anywhere (although all the parts stores do carry one for my year and model).

I believe if you have a MAF, then you wouldn't have a MAP. MAF sensors are usually in the tube between the intake and air filter. As far as I know MAP sensors can either be on a bracket on the firewall behind the air filter or on the passenger side fender to the left of air filter box

 

[Cees Klumper]

Thanks, I just triple checked and there's no MAP on the firewall or on the fender. I do have a MAF right after the airbox so, mystery solved.