I am totally stumped

[TimDog]

Hello,

I am having issues with my 1990 ford ranger, 2.9L V6 Manual Tranny, 126000 miles. Hope someone can help me. You guys have come through in the past and I am praying you can help again.

Heres the deal....

First, my truck runs great when its cold and been sitting overnight, around 30 minutes of driving, it starts acting up. Second, failed HC emissions test at idle, passing is 220ppm, reading 1475ppm. On the top end, it tested out fine, no problems This was tested before idling problem progressed into below problems.

The engine accelerates fine, no loss of power, but when I let off the gas in gear, the tach starts jumping and the engine sputters and pops, I can hit the gas again and it returns to normal. As long as I am accelerating, no problems. Check engine light would come on and off, but never just stay on. I come to a stop light, and put in N, sometimes it returns to idle with no problems, but more time than not, it dies. I have to restart the engine, then it will die again, after three or four times of this, I can get it going again, then it repeats the process. Bottom line, it wont stay running, when it does, its maybe for 20 seconds or less. When it does idle, its rough and jumpy. In addition, I have had no reduction in fuel mileage. Runs great on the freeway, no problems at all.


Here is what I have done.

Put on code reader - code read TPS sensor, bad. Replaced, fixed check engine light problem. other codes included MAP sensor not reading correctly, replaced, no change. Still same issues.

Replaced cap and rotor and spark plugs. Checked all plugs, all burning clean.

Still same problems.

I hope i have provided enough information for someone to begin to help. If there are any questions, please ask.

Thanks for all your help

 

[IMenriched]

Hello,

I am having issues with my 1990 ford ranger, 2.9L V6 Manual Tranny, 126000 miles. Hope someone can help me. You guys have come through in the past and I am praying you can help again.

Heres the deal....

First, my truck runs great when its cold and been sitting overnight, around 30 minutes of driving, it starts acting up. Second, failed HC emissions test at idle, passing is 220ppm, reading 1475ppm. On the top end, it tested out fine, no problems This was tested before idling problem progressed into below problems.

The engine accelerates fine, no loss of power, but when I let off the gas in gear, the tach starts jumping and the engine sputters and pops, I can hit the gas again and it returns to normal. As long as I am accelerating, no problems. Check engine light would come on and off, but never just stay on. I come to a stop light, and put in N, sometimes it returns to idle with no problems, but more time than not, it dies. I have to restart the engine, then it will die again, after three or four times of this, I can get it going again, then it repeats the process. Bottom line, it wont stay running, when it does, its maybe for 20 seconds or less. When it does idle, its rough and jumpy. In addition, I have had no reduction in fuel mileage. Runs great on the freeway, no problems at all.


Here is what I have done.

Put on code reader - code read TPS sensor, bad. Replaced, fixed check engine light problem. other codes included MAP sensor not reading correctly, replaced, no change. Still same issues.

Replaced cap and rotor and spark plugs. Checked all plugs, all burning clean.

Still same problems.

I hope i have provided enough information for someone to begin to help. If there are any questions, please ask.

Thanks for all your help

Excellent info BTW

You may have several things still going on.

you should remove the battery cable for a couple of minutes (to clear codes) and reattach and redrive for 5-10min. and re-read codes

Considering that you already replaced other key items.
If this primarily acts up when fully warm...then that hints towards temp sensor for the engine computer ECM. these tend not to be overly expensive & if it hasn't been changed for some time...now maybe the time.

you also may have a bad connection somewhere, check all grounds.

you may also have excessive carbon build up over the vacuum ports in the upper intake and the backside of throttle plate, there is a vacuum port on the throttle body too....

...engine off...remove air intake hose and open the throttle and take a peak down the inside of the intake and if it is all thick black and gunky as well as the back side of the Throttle plate/butterfly. It maybe just as easy to remove the upper intake and give it a good cleaning, in this way you don't run the risk of cutting a chunk of carbon loose and getting it lodged under a valve and causing more damage. Yes this would require a new upper intake gasket, but it would also eliminate it as a cause.

It also might be a CO2 sensor gone bad...most suggest that unplugging it, redrive (tuck wire away from exhaust) and if symptoms improve then that's the issue.

Lots of things to check, do 1 thing, test, and move on, do too much at once, you wont' recognize what the real culprit is.

 

[almostclueless]

That WAS a very good post.


The HC and tach indications make me wonder about the ignition module and associated wiring (it's an old truck).


BTW, I'd use a good brand of ignition module if the old one tests bad.....it appears to really matter.

 

[TimDog]

thank you for all your info. I will try the battery cable, and see if I can pull a few codes. Another bit of info, the problems will occur when then engine has cooled of for awhile or sitting for an afternoon. The best driving I have found is when is has been sitting overnight, weird, huh? Ok, i have a question. Are you talking about an O2 sensor or a CO2 sensor. wouldnt the check engine light stay on if it were that. Not sure, just a thought. As far as the carbon buildup, I did not notice anything too bad when I checked that out, It has always been pretty clean. Should I try plug wires, or test the coil? Could a bad IAC valve or bad EGR cause this? Just trying to brainstorm a little. I really don't want to take the truck in if I don't have to. Thanks again in advance. You guys and gals are great.

 

[TimDog]

thank you for all your info. I will try the battery cable, and see if I can pull a few codes. Another bit of info, the problems will occur when then engine has cooled of for awhile or sitting for an afternoon. The best driving I have found is when is has been sitting overnight, weird, huh? Ok, i have a question. Are you talking about an O2 sensor or a CO2 sensor. wouldnt the check engine light stay on if it were that. Not sure, just a thought. As far as the carbon buildup, I did not notice anything too bad when I checked that out, It has always been pretty clean. Should I try plug wires, or test the coil? Could a bad IAC valve or bad EGR cause this? Just trying to brainstorm a little. I really don't want to take the truck in if I don't have to. Thanks again in advance. You guys and gals are great.

 

[almostclueless]

If you arent particularly familiar with electronics, it may very well be cheaper to take it to a dealership instead of throwing parts at it.

 

[IMenriched]

thank you for all your info. I will try the battery cable, and see if I can pull a few codes. Another bit of info, the problems will occur when then engine has cooled of for awhile or sitting for an afternoon. The best driving I have found is when is has been sitting overnight, weird, huh? Ok, i have a question. Are you talking about an O2 sensor or a CO2 sensor. wouldnt the check engine light stay on if it were that. Not sure, just a thought. As far as the carbon buildup, I did not notice anything too bad when I checked that out, It has always been pretty clean. Should I try plug wires, or test the coil? Could a bad IAC valve or bad EGR cause this? Just trying to brainstorm a little. I really don't want to take the truck in if I don't have to. Thanks again in advance. You guys and gals are great.

Yes O2 sensor, my bad.
thinking if it was the IAC, it would do this weather cold or warm. BUT, that being said, couldn't hurt to clean it up as well.

as far as the EGR goes, pretty sure after 88' they did NOT have them on...so that rules it out.

Certainly new plug wires couldn't hurt, exspecially if they have some age on them.

On to carbon build up; remove a threaded port and also take a gander at it, if there isn't sign of crusting over....then , maybe you could get by with getting it running and spray some carb cleaner down it with a high idle. But carefull not to flood it out.

and yes the TFI,(aka ignition module), could also give you these symtoms.
take it off and take to your favorite parts store, they "should" test it for free.
concidering that it acts up mostly when warm take a hairdryer along, give it a hot/warm blast while testing (hold approx 6"-10" away) and run the test at least 3 times. If it still checks good then it's not the problem, If it is abit inconsistant in the testing results, change it.

 

[dirtsquirt]

Hello,

I am having issues with my 1990 ford ranger, 2.9L V6 Manual Tranny, 126000 miles. Hope someone can help me. You guys have come through in the past and I am praying you can help again.

Heres the deal....

First, my truck runs great when its cold and been sitting overnight, around 30 minutes of driving, it starts acting up. Second, failed HC emissions test at idle, passing is 220ppm, reading 1475ppm. On the top end, it tested out fine, no problems This was tested before idling problem progressed into below problems.

The engine accelerates fine, no loss of power, but when I let off the gas in gear, the tach starts jumping and the engine sputters and pops, I can hit the gas again and it returns to normal. As long as I am accelerating, no problems. Check engine light would come on and off, but never just stay on. I come to a stop light, and put in N, sometimes it returns to idle with no problems, but more time than not, it dies. I have to restart the engine, then it will die again, after three or four times of this, I can get it going again, then it repeats the process. Bottom line, it wont stay running, when it does, its maybe for 20 seconds or less. When it does idle, its rough and jumpy. In addition, I have had no reduction in fuel mileage. Runs great on the freeway, no problems at all.


Here is what I have done.

Put on code reader - code read TPS sensor, bad. Replaced, fixed check engine light problem. other codes included MAP sensor not reading correctly, replaced, no change. Still same issues.

Replaced cap and rotor and spark plugs. Checked all plugs, all burning clean.

Still same problems.

I hope i have provided enough information for someone to begin to help. If there are any questions, please ask.

Thanks for all your help

Had very simular symtoms would run great untill it got warm outside, then would just die, wait a few moments it would start again like nothing happened, changed the relays computer and fuel pump (both were getting hot to the touch, problem went away

 

[MAKG]

It can get expensive and frustrating to guess.

An ignition miss CAN cause these issues, but ONLY if accompanied by a false lean code. The engine is almost certainly rich. The question is, what is the O2 sensor seeing? Remember O2 sensors sense oxygen and don't care at all about fuel, and a miss will make both, even if it's a rich miss.