Misfire help 2.9

[1990HossEdishun]

Been chasing my tail on a misfire on both cylinder 1 and 2 that could the spark plugs almost immediately. Both passenger side. The truck runs good at idle and drives fine on the flats but I live in an extremely hilly area and it bogs down real bad going uphill. I bought it with a service bed and it never liked the steep 6 or 7 percent grade hill I take to work everyday. It would only go about 45 up it. But since the misfire started i tried taking off the bed and it still struggles to go up hill even that fast.

Things I have tried are new plugs of course, new sparkplug wires, cap and rotor, and new fuel injectors. I have tried seafoam and berymans and they all seem to help for a few days but then it runs like dog shit again. I found a hole in the muffler as well so I took that off but still no luck in reading performance even back to how it ran when I first got it and it had that heavy box on it.

I need some help!

 

[Terrys87]

On a dark night with no lights around, pop the hood and see if you can see any pretty blues sparks popping around when idling. That can help find any bad wires. I see you replaced plug wires. One of the worse problems I dealt with was doing a tune up. I was very young and little experience. A new coil wire had an open in it. Test all your wires with a multimeter. Plenty of Youtube videos on running resistance checks.

How is your fuel filter? What other consumables need replaced? O2 sensor? some of your other sensors could just need a good cleaning. Double check that your connectors to the sensors are on good and tight.

 

[rusty ol ranger]

I would run a compression check. With 2 cylinders side by side missfiring like that....wondering if its a headgasket/head.

 

[1990HossEdishun]

Compression tested good on all cylinders both at operating temps and

I would run a compression check. With 2 cylinders side by side missfiring like that....wondering if its a headgasket/head.

Compression tested good on all cylinders. About 150 psi both cold and operating temps. Wet compression was good too. I don't have any coolant in the oil either and those two plugs are definitely carbon fouled. Not clean like any kind of leaky coolant or head gasket.

 

[1990HossEdishun]

On a dark night with no lights around, pop the hood and see if you can see any pretty blues sparks popping around when idling. That can help find any bad wires. I see you replaced plug wires. One of the worse problems I dealt with was doing a tune up. I was very young and little experience. A new coil wire had an open in it. Test all your wires with a multimeter. Plenty of Youtube videos on running resistance checks.

How is your fuel filter? What other consumables need replaced? O2 sensor? some of your other sensors could just need a good cleaning. Double check that your connectors to the sensors are on good and tight.

Hadn't thought about 02 sensor since I didn't think it was part of the feedback loop on these 90s units. How would you go about cleaning things like the TPS or other sensor. Can't use brake fluid obviously?

Fuel filter both the big can in the frame and some little inline that a previous owner added were changed last summer.

 

[I support common sense]

Check out the egr valve. You mentioned it runs fine at idle, so that might not be it. A grounded spark will definitely do it for sure. If it’s not compression then it is fuel, air or spark. Eliminate each one of those possibilities until you find the problem. Does your year support OBDII? If so, get it scanned or buy a scanner to do it. One thing that will be valuable is to look at the live data coming from the ecm and see if the fuel trim is good, also looking at the data from your o2 sensors and maf. It will be helpful to give the year of your truck and the size of the engine (I’m assuming 2.9) and perhaps the the transmission too, a sluggish automatic transmission will effect your power from the engine to the wheels.

 

[1990HossEdishun]

Check out the egr valve. You mentioned it runs fine at idle, so that might not be it. A grounded spark will definitely do it for sure. If it’s not compression then it is fuel, air or spark. Eliminate each one of those possibilities until you find the problem. Does your year support OBDII? If so, get it scanned or buy a scanner to do it. One thing that will be valuable is to look at the live data coming from the ecm and see if the fuel trim is good, also looking at the data from your o2 sensors and maf. It will be helpful to give the year of your truck and the size of the engine (I’m assuming 2.9) and perhaps the the transmission too, a sluggish automatic transmission will effect your power from the engine to the wheels.

No OBDII on the 90. It is a 1990 2.9 ranger with the 5 speed manual and 4x4. I will look tonight for spark grounding out somewhere as well as making sure all those sensors appear firmly connected. Air filter is also new last summer so I'll pull it and hit it with the air compressor.

 

[rusty ol ranger]

Try spraying some ether around the lower intake ports on those cylinders.....maybe the gasket is bad and its a vacuum leak

 

[89longbed]

It's posible the injectors for 1 and 2 aren't closing correctly (dirty) and this is causing those two cylinders to run rich, plus the EEC is seeing a rich signal from the O2 sensor and then leaning out all of the injectors to compensate. You can clean out the injectors (see YouTube). If this idea is correct you should lose fuel pressure in the manifold quicker than you will with all of the injectors closing correctly, like in an hour. Pressure is suppose to hold for a couple weeks. Problems with the pressure regulator could affect this.

Do you know how to read the codes for a system using OBD1? There's plenty of info on the web and I think the Hayes manual covering up to 1992 explains the process.

 

[1990HossEdishun]

Update. The sensors all appear to be secure well and I've eliminated a vacuum leak as I sprayed ether on all the lines and along the gaskets. No blue sparks from grounding out anywhere either. The throttle body was surprising dirty from the last time I seafoamed two months ago when this all started so I pulled it and cleaned it well as well at the MAF/TPS.
The 02 sensor was filthy though. Covered in the same carbon build up as the sparkplugs. I am soaking it over night in gasoline with a little berymans B12 and will reinstall tomorrow. I will also be putting new plugs in those cyliyinstead if just cleaned off fouled ones like I have been doing.

 

[Terrys87]

The two brass water temp sensors above the thermostat I just clean with a wire brush. The Idle Air Control, I keep the electronic part up and spray the carbon out of it.

 

[I support common sense]

Been chasing my tail on a misfire on both cylinder 1 and 2 that could the spark plugs almost immediately.

Your saying it “fouls” the spark plugs almost immediately? Is there any oil on them? What is the color of the tip? It should be a light tan not a dark brown or a black. Sounds like you know what your doing, but I thought I’d ask so that way the rest of us know so we can eliminate possibilities in our heads. I think that if it’s only in 2 cylinders then it is definitely not a sensor issue. Try the injectors and pull them on those misfiring cylinders. Could be a fuel pressure regulator, but it would effect all the cylinders not just 2 I think.

 

[I support common sense]

Obd 1 scanner is on sale right now on Amazon $25, but from what I understand you don’t need it, you can do it with a jumper wire and the check engine light I think.

Amazon.com

This fella has a YouTube video that details it well, I don’t own any obd1 vehicles, so I can’t help very much in that area.

 

[1990HossEdishun]

Your saying it “fouls” the spark plugs almost immediately? Is there any oil on them? What is the color of the tip? It should be a light tan not a dark brown or a black. Sounds like you know what your doing, but I thought I’d ask so that way the rest of us know so we can eliminate possibilities in our heads. I think that if it’s only in 2 cylinders then it is definitely not a sensor issue. Try the injectors and pull them on those misfiring cylinders. Could be a fuel pressure regulator, but it would effect all the cylinders not just 2 I think.

when this all started about a month ago initially I just figured it was time for a tune up so I replaced the spark plugs and drove off. It drove great for a day or two then started having the same problems. I pulled the plugs to look at them and those two were fouled. It's a black sooty fouling, no oil. I figured the next easiest fix was new wires, cap and rotor. And a seafoam hot soak. Again drove great for a day or two then symptoms returned. That's when I pulled the intake plenum off to replace all the injectors at once since it was kinda time intensive and I didn't want to replace other injectors later. Again drove good for a few days and I thought for sure it was fixed then it started misfiring again and I pulled the plugs and sure enough those two were fouled. I then performed the compression test with a friend and the compression was a little lower in those two cylinders so we performed and piston soak and oil change and it drove great for a week and the compression on all cylinders was solid about 150 psi. Then symptoms returned but only fouled the #2 cylinder. Friend and I checked compression again thinking it was the problem but all cylinders test the same still. He thought the weight of the bed causes the engine to work too hard and foul plugs so I pulled the service box off and the symptoms were lessened but still there. That's when I decided to ask you all at the ranger station for some help.

Since cleaning the sensors and soaking the fouled oxygen sensor I haven't put it back in to drive it yet because it was a real down poir yesterday and I didn't want to lay in the mud of my dirt drive way. If it drys out enough this afternoon I should be posting an update.

 

[SenorNoob]

I wouldn't expect to be able to clean an O2 sensor. I rarely even get it to work with spark plugs.