89 Ranger 2.9 auto won't rev past 1500 when warm

[Z3CHYD]

'86 doesn't have a functioning check engine light, but pulling codes will get you closer to what's going on. Run a KOER test when the engine is fully warm

it's an 89

 

[a31ford]

I finally got mine in to my shop, (10 other projects finished, yay !) anyhow, it's getting a transplant, (all 3, eng, tans, t-case)

I'm going to figure this out yet.... (the transplant is NOT part of this issue, it's simply getting one because all 3 need it)/

Greg

 

[sjr53]

When my '88 ran like that, a new MAP sensor fixed it.

 

[kbold]

my 88 2.9 does the same thing every once in a while, ill be driving and itll start motor boating out the exhaust and wont rev past a certain rpm... or even when im sitting idling after driving for a while itll start acting up and the idle starts flucuating between 400-1000.. making the truck stutter and shake. replaced IAC, TPS, and soon gonna try new ecu..

 

[a31ford]

I'd check the vacuum hose on the back of the fuel regulator (at the far back of the fuel rail) to see if it has any gas in it (broken diaphram). Mine was, replaced regulator and all the above symptoms went away.

Greg

 

[kbold]

i checked for fuel in the vacuum line and there was none, i tryed pulling codes off the truck to because the cel started flashing at me. which is weird cuz it flashes only until trucks warmed up then it gos away and doesnt throw anymore codes and runs fine again. just gutless. im thinking my timing is off to i hooked the o2 sensor back up and now my idle is sitting at 1300rpm... and not kicking down.


came up with EGR feedback sensor/ and evap system voltage below 0.01 or whatever. i have no clue where my egr feedback sensor would be.. any pics would be great. i tryed doing a timing check to with the diagnostic tool and it wouldnt gimme any results.. so im guessing what i said up top is my timing is off? causing number 6 cylinder to not fire right?

 

[a31ford]

It appears that many different problems produce the same results (the 1500 gutless wonder thing...)

I have to eat my words above, because 40 or so starts later, the above problem started again after the regulator replacement, BUT it did get WAY better gas mileage.....

I've pulled the engine, transmission, and transfer case (see thread "one sick puppy" http://www.therangerstation.com/forums/showthread.php?t=128820)

ONCE it's back together, I'm gona beak out the scope and probe the ECM in real time (have all the info on this type of ECM, even internal schmatics).

I'm going to FIX this problem yet, even it it takes me to 80 (if I live that long).

Greg

 

[Dugan]

This is the same issue I had after wheeling last night. It started when I was going up a sand hill and kinda started slipping then I lost what felt like my fuel. If i barely touch the gas, like 1/4" into the pedal and shift like a snail i can get to like 45 mph but it will hesitate. The motor sounds like it has a wet dizzy kinda, but I didnt hit any mud really, or atleast not fast enough to put it up that high.
Im gonna try that FPR test tonight after I replace my fuel Filter and see whats going on. Weirdest thing.



Edit: I do get a check engine light after the truck warms up but I have no access to a OBD1 scanner

Mine will rev normal when in neutral, I forget if it would with the clutch down but I believe it did. I know I have a clutch thats just about shot. Could that cause this?

 

[a31ford]

As far as the ford goes, I'm really wondering if it's the puter, as everything is ok, until about 40 starts or so (KAM memeory ?>?) if I clear the codes, it's go again, It still could be a sensor (clearing codes causes the puter to "re-learn the sensors") I'm leaning towards the MAP sensor, BUT, until I scope (oscilloscope) the output of the MAP (should be a square-wave pulse train) I won't know for sure.

BTW, love the 49, I have a 57 chev 1 ton (but not as nice as a 49)....

Greg

BTW, OBD1 can be read from the engine light. see info on the main page about this .

 

[Dugan]

As far as the ford goes, I'm really wondering if it's the puter, as everything is ok, until about 40 starts or so (KAM memeory ?>?) if I clear the codes, it's go again, It still could be a sensor (clearing codes causes the puter to "re-learn the sensors") I'm leaning towards the MAP sensor, BUT, until I scope (oscilloscope) the output of the MAP (should be a square-wave pulse train) I won't know for sure.

BTW, love the 49, I have a 57 chev 1 ton (but not as nice as a 49)....

Greg

BTW, OBD1 can be read from the engine light. see info on the main page about this .

Any updates? Im taking off my TFI and checking it tonight.

 

[Dugan]

Any updates? Im taking off my TFI and checking it tonight.

TFI checked out good at autozone,

Took the FPR and TPS off my other motor and put em on. I Have fuel line disconnect tools and they wouldnt fit the fitting on the FPR so I cut the little plastic line between the two and replaced it with a clear hose. After messing with it I believe the hose could have been Kinking. Put new FPR on and TPS and the truck....so far.... is running like a champ

 

[Dugan]

That didnt last long.

Thats while engine off key on. When you turn on the truck the psi drops to 30. And when you nail the gas will jump to 45 then back to 30 quick. Then it will drop to 10 when its bogging out.

After bogging it out around the corner and coming back with the gauge on, the line I added between the fuel line and FPR was empty. I dont know why this happened, but it looks like this motor is restricted somewhere. This is a brand new fuel pump too only has like 400miles MAX on it.

 

[1994STX]

I don't have any of my reference material in front of me, but if it has an EGR valve, you might want to check it, also. My first thoughts were plugged converters.

 

[camobancher88]

Mines doing almost the same thing.. i dont have a rpm gauge so its hard to tell what the rpm its doing it at.. i guessing right around 3000 do to the sound of it... An only sometimes does it do this... back fires like crazy with absolutly no power! ill keep my eyes on this tread

 

[camobancher88]

my truck is doing almost the same thing... cant tell at what rpm due to no rpm gauge.. but im guessing based in the sound its around 3000rpm... and only some times does it do this will run fine then all of a sudden no power back firing like crazy!! then run fines again a few seconds later... not sure what to do next.. changed the TFI, and ever since then did it do this.. changed the plug wires today and hasnt done it since that... ill keep an eye out on this thread if it started to act up again...