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Any advice before I bust out the parts cannon?


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87 wagoneer I-6 aw4

 

Last week it rained. I drove through some flooded intersections and everything was fine. PO put cutout vents in the hood so I was worried about water getting in, but I survived most of the day. After it had stopped raining and I was on dry asphalt and came to a stop light. After it turned green, my tranny decided it wanted to stay in first. I also was not able to shift manually through the gears. I pulled the inline tcu fuse and was able to shift manually and get home.

 

Note: While all this was happening, the motor was running fine.

 

After some diagnostics, I ended up replacing the tps and solving the shifting issue, however now the motor is running bogged down and underpowered. My tps voltages are within spec. I'm just wondering if anyone has experienced this before I start replacing sensors.

 

Also, i was unable to find any vacuum leaks, by to my understanding, that would cause a high idle, not the very low one that I have.

 

Advice? Thanks!

 

 

87' 4x4 Sportruck

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How deep of a flooded intersection are we talking? Most of the engine bay can get a bit wet without problems, although full submersion is a bit different. If the alternator's not putting out the full voltage I can see that causing some issues with various sensors because they'll all be getting too low voltage. But I only say this cause the alternator's low in the bay and can be susceptible to water crossings. 

Did you unplug the idle air controller (IAC) or otherwise do something with it while you were messing with the TPS?

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How deep of a flooded intersection are we talking? Most of the engine bay can get a bit wet without problems, although full submersion is a bit different. If the alternator's not putting out the full voltage I can see that causing some issues with various sensors because they'll all be getting too low voltage. But I only say this cause the alternator's low in the bay and can be susceptible to water crossings. 
Did you unplug the idle air controller (IAC) or otherwise do something with it while you were messing with the TPS?


About 2.5' of water. And no I didn't unplug the iac. I installed the new tps, adjusted voltages and fired her up. On the first turn of the key, the idle stuck at 3k. I shut it down, and turned the key again, still stuck at 3k. I turned her off, waited a few minutes and turned it back on, the idle went up to 3k and dropped alllllll the way back down to about 500 or less and stayed there. She sounds super lopey almost like it wants to die, but not quite. Idle and acceleration are smooth, just underpowered.


87' 4x4 Sportruck
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Did you do anything else other than the tps? More than likely the tps is the issue.  They do come bad right out of the box sometimes. 



I pulled, cleaned and dried all connectors from tranny to throttle body. The tps is all I have replaced so far, is it possible that it's bad but still reading correct voltages?


87' XJ Wagoneer I-6 AW4 NP242
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Just now, Kyleinreallife said:

 

 


I pulled, cleaned and dried all connectors from tranny to throttle body. The tps is all I have replaced so far, is it possible that it's bad but still reading correct voltages?


87' XJ Wagoneer I-6 AW4 NP242

 

 

Yes it is.  It's one of those sensors that can test good but still be bad.  It's susceptible to environmental changes such as temperature. 

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40 minutes ago, Kyleinreallife said:

I pulled, cleaned and dried all connectors from tranny to throttle body. The tps is all I have replaced so far, is it possible that it's bad but still reading correct voltages?

87' XJ Wagoneer I-6 AW4 NP242

 

 

 

Including the CPS connector?

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I'm in nearly the same boat, my friend.  VERY low idle, which stalls and sometimes dies at traffic lights once I begin to accelerate.  I think what got me to this was not flooding as in your case, but a fuel tank replacement.  I think I screwed something up with all of the hour-long engine cranking I did to get the engine to start.  Hasn't been the same since.  Must of fried something.  

 

I picked up a new CPS but hadn't had time to try it yet.  Using a different cleaned throttle body, different adjusted TPS and different IAC (all used) didn't help.   My plan is to toss on the new CPS, and if that doesn't help, then multimeter-check TPS, EGR, CPS.  If that doesn't identify and help, then its time for me to load that cannon. 

 

Frustrating I know.  

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2 hours ago, Kyleinreallife said:


Would the crank sensor affect idle and power? Or just start up effectiveness?
 

 

If the signal out of it is garbage it will cause the ignition and injection timing to be wrong.  Personally they've always either worked or not for me, that is either the trucks runs or it doesn't.  When the signal from them is weak the crank time will increase,  until eventually you'll get a no start (typically when it's hot the first couple times, it will normally restart once it cools).

 

There's no reason not to clean the connector on it, but I doubt it is the issue.  I'm guessing the TPS is producing erratic output through its range of travel.  You can test the sweep on it with a multimeter if you have a decent one.

 

There may well be something else that is wet and unhappy, but this happened last week...  Unless you're parking it in a lake I doubt moisture is still the issue.

 

Your original TPS may have dried out enough to work by now too.  Especially if you put it somewhere hot.

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If the signal out of it is garbage it will cause the ignition and injection timing to be wrong.  Personally they've always either worked or not for me, that is either the trucks runs or it doesn't.  When the signal from them is weak the crank time will increase,  until eventually you'll get a no start (typically when it's hot the first couple times, it will normally restart once it cools).
 
There's no reason not to clean the connector on it, but I doubt it is the issue.  I'm guessing the TPS is producing erratic output through its range of travel.  You can test the sweep on it with a multimeter if you have a decent one.
 
There may well be something else that is wet and unhappy, but this happened last week...  Unless you're parking it in a lake I doubt moisture is still the issue.
 
Your original TPS may have dried out enough to work by now too.  Especially if you put it somewhere hot.



If the output on the sweep were off wouldn't that cause erratic idle/acceleration? My idle, acceleration and rpms at speed are all steady, just underpowered...like not enough fuel or too much air.


87' XJ Wagoneer I-6 AW4 NP242
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43 minutes ago, Kyleinreallife said:

If the output on the sweep were off wouldn't that cause erratic idle/acceleration? My idle, acceleration and rpms at speed are all steady, just underpowered...like not enough fuel or too much air.

 

 

 

Maybe, maybe not.  Acceleration and held throttle would likely be bad, but it's surprising what will or won't happen.

 

Did you verify you didn't suck water through the engine?  Looked at the air filter?  Pulled the plugs?  Last engine that I saw suck water was mysteriously low on power, then a couple days later it popped the top off a piston and blew the ring into the cylinder head...

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Maybe, maybe not.  Acceleration and held throttle would likely be bad, but it's surprising what will or won't happen.
 
Did you verify you didn't suck water through the engine?  Looked at the air filter?  Pulled the plugs?  Last engine that I saw suck water was mysteriously low on power, then a couple days later it popped the top off a piston and blew the ring into the cylinder head...



Well I hope that's not the case here. I'll check the air filter, I just put new plugs in the weekend before the rain, but I'll pull them tomorrow and have a look, I'll check for milky oil while I'm at it.

Update: I just put the 2nd new tps on and had the same result. Adjusted voltages, stuck with hi idle (1500), drove it around the block. Turned it off and then turned it back on, rpms shot up to 2k then dropped back down to under 500 and stayed there....I'm at a loss.


87' XJ Wagoneer I-6 AW4 NP242
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Bump

So today I, checked all my sensors and they all tested fine, as far as I could tell. Checked cts, crankps, mat, map, o2, tps, iac. I installed new plugs, cap, rotor, pulled and cleaned the throttle body. Checked all vac lines, tightened all manifold and valvecover bolts.

I started diving into the injectors as I was running out of daylight. I pulled them one by one to see how the affected engine idle, all of them lowered the idle except for #5, no effect. So I tested voltage output from connector, 11.something. Checked resistance on the injector, ford d5b was about 14.5 ohms...both within spec as far as I know. Was planning on running injector cleaner through the system and then actually pulling the fuel rail and inspecting them more closely. Not sure if PO knew what they were doing when the installed the injectors and I'm no sure if those particular ones are compatible. It's always ran rich since I bought it but now it's running underpowered....


Opinions?


87' XJ Wagoneer I-6 AW4 NP242

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If you have a plugged injector the O2 sensor will read lean and enrich the ones that work, effectively making the other cylinders rich (and that one will remain dead).

 

You can try to clean it by throwing it in a container of solvent, Seafoam, kerosene, etc and cycling the injector with a battery (9V will work for this).  If you have an ultrasonic cleaner that will work well too, or put it in a cup and leave it on something that shakes (generator, air compressor, washing machine) for a while.  Don't blow yourself up or burn anything down.

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If you have a plugged injector the O2 sensor will read lean and enrich the ones that work, effectively making the other cylinders rich (and that one will remain dead).
 
You can try to clean it by throwing it in a container of solvent, Seafoam, kerosene, etc and cycling the injector with a battery (9V will work for this).  If you have an ultrasonic cleaner that will work well too, or put it in a cup and leave it on something that shakes (generator, air compressor, washing machine) for a while.  Don't blow yourself up or burn anything down.



Sounds exactly like the issue I'm having, I'll pull the fuel rail today. Does it matter which injector goes back into what port?

Also, could there be any correlation between the replacement tps (to fix the shifting issue) and the injector plugging up? Or just a snowball effect coincidence?


87' XJ Wagoneer I-6 AW4 NP242
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