has spark, no injector pulse. - JeepForum.com

 
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post #1 of 8 Old 07-26-2012, 08:58 AM Thread Starter
rude_dog_62471
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has spark, no injector pulse.

i bought a 86 comanchie 2.5 4 speed rwd the guy that had it was going to scrap it, this truck set in his barn since early 90's has les then 100'000 miles i had to save it but heres my problem, i have put a lot of new parts on it that had been robbed over the years, i have it to where its 95% ready to run, it has good spark but no pulse to the injector i tested it with a diode and nothing, i went to autozone.com and got the page on how to test the ecu but have not done that yet, if the ecu was bad would it still have spark? if you put a little gas down the throttle body she starts right up, but then dies. could i just swap in a carb i do know i need a new injector it only reads 1.5 ohms and that and the ecu will probly be about as much as a new carb, although i would like to keep it injected, and if it come down to it, where do i get a new or refurbished ecu? any help is great.

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post #2 of 8 Old 07-28-2012, 05:47 PM
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The fuel pump is probably bad, or the hose is rotted off of it in the tank.

Do a fuel pressure check next.
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post #3 of 8 Old 07-29-2012, 06:12 PM Thread Starter
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good fuel pump it has good pressure at the throtlebody i checked the injector wit a diode and it had no pulse just checked the ecm it was good too
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post #4 of 8 Old 07-29-2012, 06:16 PM
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Make sure the braided cable is there from the driver's side back of the head to the firewall. There are also some ground wires at the engine dipstick tube stud. Remove and clean them up til perfect.
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post #5 of 8 Old 07-30-2012, 08:21 AM Thread Starter
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k thank you i will look for this ground wire and let you know, seems like that is what it would be to me. i did try ohming the light blue injector wire to a good ground and it had no response, hopefuly i solve this problem soon, this truck is way to nice to be seting in a barn.
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post #6 of 8 Old 08-08-2012, 08:42 AM Thread Starter
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i still cant figger this out and i'm getting tired of messing with it, anybody have a running truck to trade for this, it's in near perfect cond. im just stumped and am tired of walking to and from work in this heat, doesent matter what the trade looks like as long as it runs good.
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post #7 of 8 Old 08-14-2012, 01:59 PM Thread Starter
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any body want to trade a tbi intake and throttle body for a carb and matching intake i am just going to do away with the tbi and go old school so im looking for a straight up trade mines a 86 2.5 and the throtle body has been rebuilt.
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post #8 of 8 Old 08-16-2012, 06:31 AM
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If it has this C101 connector, clean it.



Renix Jeep C101 Connector Refreshing


The C101 connector on 1987 and 1988 Renix Jeeps was a source of electrical resistance when the vehicles were new. So much so that the factory eliminated this connector in the 1989 and 1990 models. The factory recommended cleaning this connector to insure the proper voltage and ground signals between the ECU and the fuel injection sensors. We can only imagine how this connector has become a larger source of voltage loss and increased resistance over a period of almost 25 years. The C101 connector needs to be cleaned at least once in the lifetime of your vehicle. Chances are it’s never been done before.

Almost every critical signal between the engine sensors, injectors, ECU, and some to the TCU, travel this path through the C101 connector.

The C101 connector is located on the driver’s side firewall above and behind the brake booster. It is held together with a single bolt in it’s center. To get the connectors apart, simply remove the bolt and pull the halves apart. You will find the connector is packed with a black tar like substance which has hardened over time.
Take a pocket screwdriver or the like and scrape out all the tar crap you can. Follow up by spraying out both connector halves with brake cleaner and then swabbing out the remainder of the tar. Repeat this procedure until the tar is totally removed. This may require 3 or more repetitions. Wipe out the connectors after spraying with a soft cloth.

If you have a small pick or dental tool, tweak the female connectors on the one side so they grab the pins on the opposite side a bit tighter before bolting both halves back together.


Revised 07-17-2012
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