88 Ranger 2.9 fuel pressure issues??

[Paulos]

A vacuum leak from a brake booster could cause a lean condition and give you the code 41. You need to remedy any vacuum leaks before proceeding. Don't forget to disconnect the battery to reset the ECM (I usually give it at least 20 minutes). Then test again. You didn't say if the truck had sat for a while, or not, before you bought it.

 

[CzyRanger]

Valve covers leak on 2.9s. The blue felpro gaskets fix this. There is a very light torque spec on it.

Do not take the lower intake off. You do.t need to.

You are running lean. I.will bet you do not have a fuel pressure issue beyond dirty injectors. Those exhaust pops are lean condition. I set my engine up to do this when I'm on decel intentionally. I like the sound. But I did it by setting my air fuel ratio up to 16.5-19.6 in order to cause it. Lean=pops. That tells me tour O2 is working and your computer is working to control O2.

The best thing you can do right now.is pull your fuel rail and clean your injectors. That will get the "it has to he a fuel problem" line of thinking out of your head.

Bird is right with his propane torch advice.

Your exhaust manifolds probably leak. This is a pain in the ass to fix. I have extra manifolds if yours are rotted out.

I mean... Do YOU think it's worth it to clean the injectors? Honestly... I don't have any one thing stuck in my head. It's kind of all over the place if you couldn't tell. ? I know paulos suggested the injectors but haven't heard back from him on my latest updates. Again... Thank you for all the help. It's much appreciated!

 

[Paulos]

If the injectors have never been cleaned, it would definitely help to clean them (it's been 31 years). Is that causing your problem? Not necessarily. I highly doubt it's your upper or lower intake. If I were you and I was strapped for cash, or just want to test a bit more, I would use some Permatex Aviation gasket sealer (the brown liquid/syrupy stuff) or a light coat of silicone on the old intake gaskets and reassemble it; otherwise, the gaskets run about $10. Check the torque on the lower intake and make sure the bolts are snug, but not too tight. The oil leaks at the valve covers won't affect the performance of the engine, unless it leaks way too much and starts an oil fire (unlikely because your cats are gutted). Check your timing to make sure it's right. If your brake booster is leaking and it's hard to brake, you're probably already used to it not braking very easy; so if you have a safe place to test it (I'm not telling you that you should, but I would if it was safe) disconnect the booster's vacuum line from the intake and plug it (if it's bad, it may be doing nothing but leaking already). Check the wiring at the rear passenger side of the engine where the wiring for the O2 sensor and trans is routed, making sure that there is a ground bolted to the back of the PASSENGER side head (it's probably orange), and that no wires are melted by resting on the exhaust. Reconnect your O2 sensor. Disconnect your battery for 20 minutes and reconnect it. Start it and let it warm up, then take it for a test drive. When you get back, pull the codes again to see if you still have the code 41. Then let us know how it goes.

 

[CzyRanger]

If the injectors have never been cleaned, it would definitely help to clean them (it's been 31 years). Is that causing your problem? Not necessarily. I highly doubt it's your upper or lower intake. If I were you and I was strapped for cash, or just want to test a bit more, I would use some Permatex Aviation gasket sealer (the brown liquid/syrupy stuff) or a light coat of silicone on the old intake gaskets and reassemble it; otherwise, the gaskets run about $10. Check the torque on the lower intake and make sure the bolts are snug, but not too tight. The oil leaks at the valve covers won't affect the performance of the engine, unless it leaks way too much and starts an oil fire (unlikely because your cats are gutted). Check your timing to make sure it's right. If your brake booster is leaking and it's hard to brake, you're probably already used to it not braking very easy; so if you have a safe place to test it (I'm not telling you that you should, but I would if it was safe) disconnect the booster's vacuum line from the intake and plug it (if it's bad, it may be doing nothing but leaking already). Check the wiring at the rear passenger side of the engine where the wiring for the O2 sensor and trans is routed, making sure that there is a ground bolted to the back of the PASSENGER side head (it's probably orange), and that no wires are melted by resting on the exhaust. Reconnect your O2 sensor. Disconnect your battery for 20 minutes and reconnect it. Start it and let it warm up, then take it for a test drive. When you get back, pull the codes again to see if you still have the code 41. Then let us know how it goes.

Got it. Will do. Thanks so much!

 

[PetroleumJunkie412]

I mean... Do YOU think it's worth it to clean the injectors? Honestly... I don't have any one thing stuck in my head. It's kind of all over the place if you couldn't tell. ? I know paulos suggested the injectors but haven't heard back from him on my latest updates. Again... Thank you for all the help. It's much appreciated!

Yes. Absolutely worth doing. You'd be amazed at how.much sh*t builds up in them.

 

[Bird76Mojo]

You don't have to buy a propane torch unless you think it will come in handy in the future. Here's another method:

 

[CzyRanger]

You don't have to buy a propane torch unless you think it will come in handy in the future. Here's another method:

@Bird76Mojo Well I have carb cleaner so I'll just use that. Great! I will post results. Thanks so much!

 

[Bird76Mojo]

@Bird76Mojo Well I have carb cleaner so I'll just use that. Great! I will post results. Thanks so much!

Just be careful and keep your face far enough away in case of any fire.

 

[Bird76Mojo]

@CzyRanger hit me up in a private message with a video about his new idle problems. I posted this reply to him in the PM. I'm just posting it here to keep it all in one thread. Hopefully he'll post the full question and video here.

If anyone sees anything wrong with the advice I've given then please speak up and I'll edit it.




Not sure where to start here really. I'd start by unhooking the battery for a while. It will reset the ECM and let it re-learn it's idle strategy.

Unhooking 90% of your vacuum hoses will cause the idle to change. The one to the fuel vapor canister won't change the idle unless the fuel vapor recirculating valve is opened up to let the engine burn off the vapors in the canister. I believe the ECM only opens it up during part-throttle cruising to increase fuel mileage and to reduce fuel vapor emissions.

You could start by checking your TPS sensor voltage with key on and engine off. If it's reading too high with the throttle closed, then someone may have threaded the throttle body butterfly screw (commonly called the idle screw but it's not really) in too far trying to correct some previous issue. If you open the throttle, the TPS voltage should rise and fall smoothly. If it doesn't then it's probably defective. You can check the voltage by probing the appropriate wires with sewing needles and putting your voltmeter on them.

Is your SPOUT connector plugged in? If the SPOUT is unplugged, the ECM isn't controlling the distributor timing, so the idle may be increased. You unplug the SPOUT to set the distributor timing, and then you plug it back in.

It does sound like it has a miss in the engine. You might try wearing a good rubber glove and unplugging one spark plug wire at a time until you finally pull one and nothing changes. That would be your cylinder that's missing.

Also, have you set your distributor timing with the SPOUT unplugged and using a good timing light?

 

[PetroleumJunkie412]

No.valve for fuel vapors on a 1988; just a charcoal can.

 

[CzyRanger]

@CzyRanger hit me up in a private message with a video about his new idle problems. I posted this reply to him in the PM. I'm just posting it here to keep it all in one thread. Hopefully he'll post the full question and video here.

If anyone sees anything wrong with the advice I've given then please speak up and I'll edit it.




Not sure where to start here really. I'd start by unhooking the battery for a while. It will reset the ECM and let it re-learn it's idle strategy.

Unhooking 90% of your vacuum hoses will cause the idle to change. The one to the fuel vapor canister won't change the idle unless the fuel vapor recirculating valve is opened up to let the engine burn off the vapors in the canister. I believe the ECM only opens it up during part-throttle cruising to increase fuel mileage and to reduce fuel vapor emissions.

You could start by checking your TPS sensor voltage with key on and engine off. If it's reading too high with the throttle closed, then someone may have threaded the throttle body butterfly screw (commonly called the idle screw but it's not really) in too far trying to correct some previous issue. If you open the throttle, the TPS voltage should rise and fall smoothly. If it doesn't then it's probably defective. You can check the voltage by probing the appropriate wires with sewing needles and putting your voltmeter on them.

Is your SPOUT connector plugged in? If the SPOUT is unplugged, the ECM isn't controlling the distributor timing, so the idle may be increased. You unplug the SPOUT to set the distributor timing, and then you plug it back in.

It does sound like it has a miss in the engine. You might try wearing a good rubber glove and unplugging one spark plug wire at a time until you finally pull one and nothing changes. That would be your cylinder that's missing.

Also, have you set your distributor timing with the SPOUT unplugged and using a good timing light?

@Bird76Mojo
First off... Wanted to note that I replaced the distributor and ignition control module and I did unplug the spout before timing and then plugged it back in. The 10 degree mark (which I painted white) corrected itself and is now almost exactly in-between the pointer that I originally lined it up with and the eyelet. Also... I have tried unplugging the negative battery terminal for a while. I have a multimeter. How exactly do I test the TPS and what should it read? Whats odd to me is that it was idling at 800-900 before I took everything off and cleaned stuff up etc. Thanks again guys for all the help. This is my "daily" driver and it's really hurting me having it down. ?

 

[Bird76Mojo]

On your timing, shouldn't the 10 degree mark be lining up WITH THE POINTER? Not in between the pointer and the eyelet..? It's been a long time since I had to time a 2.9, let alone, work on one, so I can't remember what the timing pointer looks like.

I guess what you're trying to say is that you timed it with the SPOUT unplugged at 10 degrees, then when you plugged in the SPOUT, the timing mark was then showing up between the pointer and eyelet??

You might have to look through the tech library on here, or Google search is sometimes easier, and find the procedure to check the TPS. It's not hard at all. I located one page for you here: https://www.therangerstation.com/forums/index.php?threads/how-to-adjust-tps-sensor-ford-fuel-injection-models.66515/

You didn't forget to plug in the coolant temperature sensor did you? That may effect idle as well.


Hopefully others will chime in before I have you on a wild goose chase. lol

 

[CzyRanger]

 

[CzyRanger]

On your timing, shouldn't the 10 degree mark be lining up WITH THE POINTER? Not in between the pointer and the eyelet..? It's been a long time since I had to time a 2.9, let alone, work on one, so I can't remember what the timing pointer looks like.

I guess what you're trying to say is that you timed it with the SPOUT unplugged at 10 degrees, then when you plugged in the SPOUT, the timing mark was then showing up between the pointer and eyelet??

You might have to look through the tech library on here, or Google search is sometimes easier, and find the procedure to check the TPS. It's not hard at all. I located one page for you here: https://www.therangerstation.com/forums/index.php?threads/how-to-adjust-tps-sensor-ford-fuel-injection-models.66515/

You didn't forget to plug in the coolant temperature sensor did you? That may effect idle as well.


Hopefully others will chime in before I have you on a wild goose chase. lol

Yes sir. That's what I meant. 10 degrees was at the pointer before I replugged in the Spout. Also... Yes the coolant temp sensor is plugged in. Haha... I don't mind the wild goose chase as long as I can get somewhere. Haha. Thanks again my friend. I appreciate you more then ya know. ?

 

[Bird76Mojo]

I wouldn't think you have a vacuum leak now, but that's another check you could always do with spraying around hoses, etc.

I'm not sure about which wires you need to probe to check with the voltmeter. In the past on my 2.9, I just probed two wires at a time until I got the voltage I was looking for. Just be sure to not let two probes touch each other and you should be fine. Set the voltmeter for the 12v or 20v setting, whichever yours has, and probe two wires. You should see the recommended voltages that were listed in the thread I linked to.


Credit to @creepinjeepster for the following: https://www.therangerstation.com/forums/index.php?threads/how-to-adjust-tps-sensor-ford-fuel-injection-models.66515/

•Closed Throttle can be anywhere between 0.6-1.0 volts
•Part Throttle is triggered @ 0.04 volts above Closed Throttle
•Full Throttle is triggered @ 2.71 volts above Closed Throttle

Throttle Position Sensor
Rotational Angle Signal Voltage
0 Under Travel 0.000
10 0.450
13 Closed Throttle 0.901
20 - 1.440
30 1.900
40 2.370
50 2.840
60 3.310
70 3.780
80 4.240
84 Full Throttle 4.538
90 Over Travel 4.538
100 5.00
Values were calculated for VREF = 5.0 volts.
These values may vary 3 percent due to sensor
and VREF variations.

Again, when opening the throttle while probing the wires, and do it very slowly, you should see a gradual rise in voltage. If the voltage all of the sudden drops to zero while you're at half throttle for instance, then the TPS is bad or your probes have come loose from the voltmeter. What we're mainly looking at here though is the voltage at closed throttle. Just to see if someone has played with the idle/butterfly stop screw in the past. If the voltage at the TPS is above 1 volt at closed throttle, then someone has probably moved the "idle" (throttle stop) screw.

You could always try to back that screw out to lower your idle, and set the idle where you want it, but then you'll have to check the TPS voltages afterwards to be sure it's correct. If you move the "idle" screw then you'll throw the TPS voltage out of range possibly. In that case you would have to loosen the TPS screws and try to rotate it, using the slop in the bolt holes to get the voltages where you need them at closed throttle. Some people have even had to hog out the bolt holes in the TPS before to elongate them a little to get it set where they need it.


I'm still hoping others will chime in here for more help, because I can't understand why your idle would increase that much after you reinstalled everything, unless your throttle cable is in a bind and is pulling the throttle part way open?