87 Renix intke backfire
#16
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Read this:
Here’s WHY distributor indexing is so important:
Distributor indexing explained
For clarification though, that’s not a cam sensor inside the Renix dizzy. It’s there to fire the injectors sequentially with the firing order. You’ll never notice if it went bad because the ECU will try to “guess” where it is and does a heck of a job at it.
As for the “timing”, it is controlled by the ECU. Ever notice how wide the tip of the rotor is? Try and wrap your head around this:
When the ECU yells “Fire” to the ignition control module, where is the rotor in relationship to the dizzy terminal? Not to the terminal yet? Past the terminal too far?
What happens to the spark/secondary ignition strength when it has to jump the Grand Canyon in comparison to shooting from a rotor tip?
#17
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
#18
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#19
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Yer nothing if not predictable! OK you wait right there, I'll get right on it.
You know as well as I it would work just fine. Just a longer crank sometimes with no phase pulse incinkerator.
You know as well as I it would work just fine. Just a longer crank sometimes with no phase pulse incinkerator.
#20
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#21
Thread Starter
Newbie
Joined: Jun 2016
Posts: 18
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From: truth or consequences, NM
Year: 1987
Model: Cherokee
Engine: 4.0
I have not got a chance to index the dist but Ive sat there with it running and tried to play with the rotation. I know i stabbed the dist the correct way even if it was a tooth off i still get no change at all when i try to dial it in. Im going to get a new cap so i can destroy the old one. If this doent work I dont know what to try next.
#22
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
I would have checked by now to see if it will rev up spraying starting fluid. Might be your engine temp circuit is telling the ECU to go max lean.
Also you should get that TPS sorted out. Gotta do it anyway, so may as well get that out of the way.
Also you should get that TPS sorted out. Gotta do it anyway, so may as well get that out of the way.
#23
Thread Starter
Newbie
Joined: Jun 2016
Posts: 18
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From: truth or consequences, NM
Year: 1987
Model: Cherokee
Engine: 4.0
I have taken the split loom off the entire length from the c101 to the end of the injectors i have seen the 2 factory splices. theres about 8 wires bunched and soldered then theres another coming from the tps and i get an ohm of resistance there but after doing the calcs im supposed to be getting .81 from the tps and the max i can get it is about .55. Its a new tps granted I got for 10 bucks from a Chinese retailer but the old one was exactly the same. Could this be my root problem? Should i run new wires from the tps to the ecm? I know the distributor is an issue but im stabbing correctly and i have tried spinning it slightly both directions. Does the housing need to be in a certain place? I mean if i move the balancer to tds on compression stroke the center spinning node will be correct and i should be able to spin the dist to the correct place to make it right. The center spinning thingamajig is whats really important right? If you get that right the outside should be a matter of spinning it until the thing is good. Im thinking the guy i got it from rebuilt it and couldnt figure this out and thats why the dist ears are cut.
#24
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Joined: Aug 2011
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I'm not convinced your distributor is in correctly.
You must use tips 12 and 13 to get that right. There is no room for error!!!
Too much thinking. Not enough verifying.
You must use tips 12 and 13 to get that right. There is no room for error!!!
Too much thinking. Not enough verifying.
#25
Thread Starter
Newbie
Joined: Jun 2016
Posts: 18
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From: truth or consequences, NM
Year: 1987
Model: Cherokee
Engine: 4.0
Ok so i did tips 12 and 13. Ive stabbed this thing about 6 times trying a tooth this way or that. I rotated the distributor so the rotor is just starting to eave the #1 node. im not getting any changes. Im so lost right now on wat my next step is
#26
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Okay, so you know that is right.
#28
Thread Starter
Newbie
Joined: Jun 2016
Posts: 18
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From: truth or consequences, NM
Year: 1987
Model: Cherokee
Engine: 4.0
I unplugged the tps and it runs the same no matter. Sometimes the intake is super loud from the iac until i move it but then it stopps and no matter how i move the tps it doesnt get loud again.
#29
Thread Starter
Newbie
Joined: Jun 2016
Posts: 18
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From: truth or consequences, NM
Year: 1987
Model: Cherokee
Engine: 4.0
I also pulled the fuel rail and turned the key to prime the rail and i use a + and - wire to each injector and they spray a nice mist shaped like a cone.
#30
Thread Starter
Newbie
Joined: Jun 2016
Posts: 18
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From: truth or consequences, NM
Year: 1987
Model: Cherokee
Engine: 4.0
I also eleminted the c101 connector. Still trying to figure out how i want to route the splitloom so ill tinker with that and then the tps to see if it helped me get it diald in