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1998 Isuzu Rodeo Question engine missing on 3 & 4 cylind

Tiny
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  • 1998 ISUZU RODEO
Engine Performance problem
1998 Isuzu Rodeo Question 4 cyl Two Wheel Drive Manual

Head gasket blew between 3 & 4 cylinder. Had the head reconditioned and installed everything to specifications. Now the engine is missing on cylinders 3 & 4. The timing is set perfectly to spec, there is 155 psi on each cylinder, both cylinders are getting fire and both injectors are operating. When I removed the plugs they had a carbon/fuel foul look to them. Also, there is no check engine light. What is your thoughts?
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Wednesday, February 10th, 2010 AT 6:36 PM

19 Replies

Tiny
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Any chance that 3 & 4 wires are crossed?
Should be 1 3 4 2 around the cap for the firing order
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Wednesday, February 10th, 2010 AT 8:28 PM
Tiny
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The firing order is correct. The one other thing that happened was the catalytic converter was glowing red. I disconnected the exhaust to ensure it was not clogged and there was no change to the 2 cylinders in question.
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Thursday, February 11th, 2010 AT 4:43 AM
Tiny
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Glowing red cat usually means way too much fuel. Were the plugs wet with fuel or sooty like carbon fouling?When itis running, put your finger on the injectors in question to see if you can feel them clicking, they may be stuck open. Test across the injectors(resistance) to see if perhaps they are shorted.
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Thursday, February 11th, 2010 AT 7:01 AM
Tiny
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The plugs were sooty looking and the injectors are pulsing. I used a stethoscope to verify.
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Thursday, February 11th, 2010 AT 7:16 AM
Tiny
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Sooty but compression is good? Check resistance across injectors. Would be nice to have it on a scanner to watch the injector waveform to see what they are doing. Have you done a leak-down test on the cylinders?
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Thursday, February 11th, 2010 AT 7:42 AM
Tiny
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I agree, it would be nice to have a scanner to watch the injectors. I keep wondering if the injector timing is off? Cam position sensor? No, I haven't done a leak down test on the cylinders. Before we changed the head gasket the truck ran fine. So, I didn't consider doing one.
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Thursday, February 11th, 2010 AT 8:04 AM
Tiny
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Definitly double check cam timing, although that would cause misfires for all cylinders on that side of the engine. Possible theinjector connectors got swapped? If you can get a "noid" light check injector pulse and compare to other cylinders to see if the light is brighter or staying on longer. Also spray around the intake with carb cleaner to see if there is a vacuum leak
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Thursday, February 11th, 2010 AT 8:30 AM
Tiny
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I have checked all installlations 3 times just cause I was thinking it had to do with me changing the head. Everything is perfect to the Chiltons manual. I never removed the wire harness from the fuel rail/injectors so they shouldn't have gotten crossed. I tested the intake gasket and it's good. I don't have a noid light so I will try to purchase one.
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Thursday, February 11th, 2010 AT 9:21 AM
Tiny
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I bought a noid tester and tested the injectors and both of them are giving me a pulsing light.
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Saturday, February 13th, 2010 AT 8:48 AM
Tiny
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Bright or dim? Compare it to the others to see.A brighter light means they are dumping more fuel. So far it has compression (same as other cyl's) spark at plugs, firing order is right and it has fuel yet it misses. Start at the beginning and do a leak down test to see if a valves are leaking that didnt show in comp test. Was any work done to the head?
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Saturday, February 13th, 2010 AT 9:12 AM
Tiny
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The head gasket blew between 3 & 4 cyl. Had the head redone. I have checked all installations 3 times and veified all installations to the manual. I have fire on all cylinders. 155lbs. Of compression or more on all cyl. And the injectors are pulsing. But when I pull the plug wire from cyl 3 or 4, there is no engine change. If I pull the wire on 1 or 2 the engine stalls. When I first started it and was trouble shooting the miss, I noticed the converter glowing red on one half. I removed the exhaust pipe and there was no difference in the engine. The firing order is correct 1342. When I removed the plugs on 3 & 4, they were carbon fouled (black sooty looking).
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Saturday, February 13th, 2010 AT 9:36 AM
Tiny
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You installed new plugs on those cylinders to no avail? Sounds liek those cylinders are rich, which can be caused by weak injectors, comp or weak spark. Does this have one or more coils?Sorry my software doesnt show. Try swapping whatever you can(injectors, wires) to the good cylinders to see if you can get the miss to follow. Check to see if EGR is stuck open, (no vacuum to valve at idle) this may do it. This is weird has everyhting but wont work. Look for anyhting on the engine that is common to those two cylinders.
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Saturday, February 13th, 2010 AT 9:47 AM
Tiny
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Yes, I put new plugs in and they did the samething. I then moved them to a good cyl. And they cleaned up. The EGR is mounted to the back of the head and is electronically controlled ( no vac), is it possible that it would affect 3 & 4 cyl?
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Saturday, February 13th, 2010 AT 10:02 AM
Tiny
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Not sure. Just looking for anything at this point since it has everything else it is supposed to
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Saturday, February 13th, 2010 AT 1:48 PM
Tiny
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What test can be performed on the EGR valve to deterimine if it is staying open?
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Sunday, February 14th, 2010 AT 5:15 PM
Tiny
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You will have to remove it to see if any carbon is holding it open
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Sunday, February 14th, 2010 AT 7:06 PM
Tiny
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Ok, I have pulled the EGR and it is operating properly. I reinstalled it with new gaskets. I went ahead and replaced the coil and module (module is part of the coil pack). The problem is still there. Do you have any other suggestions?
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Friday, February 19th, 2010 AT 6:50 PM
Tiny
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We appreciate your donation and look forward to helping you in the future. Thank you
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Monday, March 1st, 2010 AT 4:18 PM
Tiny
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You haven't resolved my issue and I have spent over $250 off of your recomendations and still have the same problem. At this time I would prefer to have my donation returned to me.
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Tuesday, March 2nd, 2010 AT 5:07 PM

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