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  #1  
Old July 23rd, 2018, 17:43
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alexgalexg alexgalexg is offline
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Over my head in problems and need help

1998 Jeep XJ AMC 4.0I6
I do not take my jeep to mechanics. I put the engine in and restored my jeep myself. I took it to a mechanic for 2 things.
1 to properly charge my new ac
2 to examine my fuel trims

Objective 1 was completed with great success. Even on the lowest setting it blows so cold I had to turn it off at one point.
I got more than I bargained for with objective 2. He did get to see the fuel trims for a brief time which he said looked very low but that he would check what they are supposed to be at in the morning. But it also suddenly threw a bunch of codes. Something that hasn't happened before to me. I will attach photos of the trims and codes below.
I asked him to check my fuel trims because the jeep pings if it's not using premium fuel.
When he went to show me the codes we had trouble connecting to the computer. Every time he plugged the tablet in the dash would stop working and the airbag light would turn on and the reader would have issues connecting. Sorry if this is scrambled but in very overwhealmed


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  #2  
Old July 24th, 2018, 08:32
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four_shot four_shot is offline
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Re: Over my head in problems and need help

Fuel trim numbers are well within normal parameters. -5% to +5% is considered normal operation.

As for the communication glitch, I lean towards an intermittant short on the data line. Probably near the OBDII connector seing as how the issue presented itself after connecting the scan tool.

Try a different scan tool just incase there are programming or hardware issues with the Autel your tech was using.
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  #3  
Old July 24th, 2018, 13:30
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Re: Over my head in problems and need help

Quote:
Originally Posted by four_shot View Post
Fuel trim numbers are well within normal parameters. -5% to +5% is considered normal operation.

As for the communication glitch, I lean towards an intermittant short on the data line. Probably near the OBDII connector seing as how the issue presented itself after connecting the scan tool.

Try a different scan tool just incase there are programming or hardware issues with the Autel your tech was using.
I'm going to do a deep reset to clear the codes. Not sure why my engine pings when if I have proper fuel trims but this is a start

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Old July 24th, 2018, 13:43
RCP Phx RCP Phx is offline
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Re: Over my head in problems and need help

If you get a chance, look at the timing numbers! You'll need something portable for this.
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Old July 24th, 2018, 17:02
trippled trippled is offline
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Re: Over my head in problems and need help

You could even check the actual timing against the computers adjusted timing to see if they match. When you put the engine in, did you replace the flex plate? And has it done it since the engine e swap?

I agree the fuel trims look normal but they also need to be seen under load. I also once had a newer f350, I connected a Ford scan tool to it and it did the same stuff. Dash going crazy, no communication, etc. Used another scanner to read it which was ok. Never had any other issues with the Ford one, owner didn't feel like chasing it since it had no other issues.
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Old July 24th, 2018, 17:06
RCP Phx RCP Phx is offline
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Re: Over my head in problems and need help

Did you ever solve the fuel injector issue?
https://naxja.org/forum/showthread.php?t=1148084
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  #7  
Old July 24th, 2018, 17:25
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Re: Over my head in problems and need help

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Originally Posted by RCP Phx View Post
Did you ever solve the fuel injector issue?
https://naxja.org/forum/showthread.php?t=1148084
The mechanic did say that under load of 2,500 rpm the trims did not change much.

I bought the xj as a barn find with a bad engine so this is the only engine I've ever driven this vehicle with and this problem has never occurred before. Only thing it's always done is ping without premium fuel which is why I suspected a lean burn.

The ksuspension fuel injectors did not have the correct flow rate for my HO 98 xj so it never did run correctly and I put the originals back in. Will be purchasing different injectors at some point.

I will do the factory reset in the morning and see if the codes come back but I have one question in the meantime that has me stumped. What else could be causing my ping! The fuel trims are aparently good so it's not running lean and it's not running hot or down on power. Does not hesitate and idles like a top. The only thing I'd have to try is the timing tip.

Maybe I'll take it back to them to see if it's off but I did the timing myself as per service manual instructions before I put the engine in so I dont see why it would be wrong.

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Old July 24th, 2018, 19:53
trippled trippled is offline
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Re: Over my head in problems and need help

I asked about the flex plate because I've seen lots of bad ones. It's possible yours is slightly causing the ignition timing to be too advanced. But you need to see where the timing actually is before you do anything else. What spark plugs do you run?
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  #9  
Old July 25th, 2018, 06:24
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Re: Over my head in problems and need help

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Originally Posted by trippled View Post
I asked about the flex plate because I've seen lots of bad ones. It's possible yours is slightly causing the ignition timing to be too advanced. But you need to see where the timing actually is before you do anything else. What spark plugs do you run?
I did not replace the flex plate but I did not see anything wrong with it to begin with so I left it as is. It was round, without bends or any damage that I could see. Anything I could do to see or test if its bad?

I run champion coppers since that seems to be what everyone says these engines run best on.

I'm not sure how to check the timing now since I cant really access the balancer without removing the radiator in order to turn the crank to top dead but with the way the distributor bolts on I feel like you can only be extremely off or spot on with the timing.

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Old July 25th, 2018, 07:46
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Over my head in problems and need help

Little update. I checked the grounds they all looked good in my opinion. I also pulled all three connectors from the computer to make sure no corrosion took hold and am happy to report that they are spotless.

I have attached a video and a picture

The picture is of some grounds I want confirmation I installed correctly. They are the grounds on the coil

The video is the cold start after the factory reset. I drove around and tested it. Threw no codes and ran like a top

https://youtu.be/95mMFsyPsDY

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  #11  
Old July 26th, 2018, 10:47
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alexgalexg alexgalexg is offline
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Over my head in problems and need help

I think the consensus is to take it to the shop so I can hook one of those 8k readers up and watch the timing. Not sure what happened the last time they hooked it up but my cheapo acutel talks just fine.

One thing I didnt do was a ticking chain and gear set because the engine was very low miles but maybe that's off by a small amount

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  #12  
Old July 26th, 2018, 13:04
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Re: Over my head in problems and need help

what do you spark plugs look like? and hows your fuel pressure?
does your gas gauge work? P0463
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  #13  
Old July 26th, 2018, 14:49
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Over my head in problems and need help

Yeah gas guage works. And my plugs looked fine last time I checked. I'm going to run a compression test at some point so I'll see the plugs then

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  #14  
Old July 27th, 2018, 08:08
jaydee1445 jaydee1445 is offline
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Re: Over my head in problems and need help

Looks like the scanner pictured is in generic mode.

IIRC my 98 had similar issues when I hooked my Maxisys 908 up using the generic OBDII setting. Entering the VIN and using the correct Chrysler adapter and mode solved the issue.
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  #15  
Old July 27th, 2018, 13:00
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alexgalexg alexgalexg is offline
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Re: Over my head in problems and need help

Quote:
Originally Posted by jaydee1445 View Post
Looks like the scanner pictured is in generic mode.

IIRC my 98 had similar issues when I hooked my Maxisys 908 up using the generic OBDII setting. Entering the VIN and using the correct Chrysler adapter and mode solved the issue.
Thank you I will make sure i put it in the vin specific mode next time i can get my hands on it

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