Question about 1985 Jeep Cherokee

1 Answer

GM 2.8 Liter Engine ECM/Coil will produce spark

Just installed a crate GM 2.8 Liter engine in a 1985 Jeep Cherokee. Engine fired up, I set the dwell, timing, and adjusted the transmission linkage. Drove the vehicle around to validate the working condition. Was happy.

The next day I went to turn over the vehicle, and it would not start. Found out I was getting not spark. I have gone through a new distributer, replaced the ECM four times (had them checked), replaced the coil, replaced the wiring harness leads to the coil, distributer, placed more grounding straps on the engine to body, and still not fire.

I have 12 volts to the correct side of the coil. Not sure where the TPS is, checked the troubleshoot tips of both Chilton, and Hayes, and wonder what I am missing. Do not think the computer is down. Something is not sending voltage to the computer to telll the ECM to work.

Have any ideas. I have been thinking of placing a points, vacuum advanced old school system in it. But wonder if there is something I am missing.

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Jeep Master
  • 22,393 Answers

Does a 85 have a ECU unit ??? sounds like it could be the switching transistor thats either under the coil or inside the distributor should look like a black plastic casing with 3/4 wires running to it then to the coil look at this first as often motor runs ,stop for a quickie somewhere and jump back in and engine will not fire up ,classic symptons

Posted on Dec 20, 2008


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

3 Answers

2000 Jeep Grand Cherokee Laredo 4.7 liter code reads p0307 turn the car off when I turn it back on started misfiring and sputtering and wont stay started now help

code p 0307 is misfiring on no 7 cylinder ====causes --- engine mechanical fault ---wiring---ignition/ fuel system--injector --ECT/MAF sensor---ECM
look for low fuel pressure or ignition control module

May 31, 2016 | 2000 Jeep Grand Cherokee Laredo

1 Answer

Firing order jeep Cherokee 2004 3.7 l v6

are you doing spark or timing a cam? what? what is JOB?
it dont matter, the engine, ecu does that, (magic)
but if it has a coil pack like my 3.8 then the coil pack must
be wire right and is marked. clearly on the pack.
they have USA jeeps and Export. country never stated here. sad huh?
and use differnent spark systems (3 types used, but 2 common)
per below.

is this not a Cheokee? the non Grand ended in 2004. so...
ill go with GC 2005, v6 3.7L
the v6 began in 2005, not 2004, but, maybe yours is the first./

the 3.7 has coil over plug, spark, 6 coils.
and the harness is fixed to those coil so all firing order are
dictated in the ECU/PCM (hard coded)

VIN engine code, K. (not stated)

and already asked, and answered .

my 3.8 (2004) jeep.
is 1,2,3,4,5,6
and is like this.

mine uses wasted spark system.

so post VIN, or tell what engine is really there.
and the true year. or build date (sticker)

so my answer is.. 2005 GC, 3.7L V6, not I-6
it has 6 cops, "coil over plugs" 6 induction coils
and runs same firing order, as the old I6 did.
but the I6 4.0liter runs a coil pack and is quite different.

times 6
all laced in, hard.

Dec 07, 2014 | 2004 Jeep Grand Cherokee

1 Answer


a jeep Silverado? is this a motor swap? franken jeep. (blue box says Cherokee)_
just one? coil?
or 2?
a key question. that.....
any coil at anytime can burn up. this is called old age or entropy.
nothing lasts for ever and for sure in a red hot engine bay.
if a 2nd one burns up,that means the dwell is too high
dwell is coil charge time.
with EFI car,s this is closely controlled at all times !!!
but there is this part called and ignitor. that can short (replaced points from IN-THE-DAY)
if the ignitor shorts, the coil primary will burn up. fast. key on.

to get help, post what engine you have, chev offers many as an option
and they all work differently (diff, EFI)

Dec 23, 2013 | 1993 Jeep Grand Cherokee

1 Answer

Where are the spark plugs

Locate the spark plug wires in the Cherokee cylinder head. In the 4.0 liter engine, the spark plugs are below the coil rail assembly. On the 4.7 liter engine, the spark plugs are located under each corresponding engine coil.

Read more: How to Replace Spark Plugs in a Jeep Grand Cherokee '

Sep 30, 2012 | 2000 Jeep Grand Cherokee

1 Answer

2006 Grand Cherokee won't start. Appears to not get fuel in cylinders. Will run on ether, opened fuel line and pump seems to be working, no fuel pressure check point so I can't use my gauge. Plugs are...

check make sure plugs sparking which is controlled by coil packs which could be faulty, very unlikely all injectors or coil packs faulty, start at basics check all fuses and engine ecm works injectors and only once car immobilizer has told engine ecm that key ok.

May 01, 2011 | 2006 Jeep Grand Cherokee

1 Answer

1990 jeep 4.2 no spark power 2 coil but no spark out of coil also have added a fuel injection,its a howel system get this a day later i go out and it starts right up wow what could it be

It is most likely the module inside of the distributor, and if you put a test light on the Neg. (-) side only of the ignition coil and crank the engine over you should see the test light pulse or blink off and on indicating that there is a dwell signal.

The dwell signal tells the ignition coil when to fire, and if there is no dwell signal then the problem is in the distributor, and if there is a dwell signal then the problem is with the ignition coil.

Jun 09, 2010 | 1990 Jeep Wrangler

1 Answer

Need ignition firing for 95 4 l. engine


ALL Jeep 4.0 motors use this firing order. Any year, any model, high output or not.

Also, the spark plug wire placement on the cap, in a clockwise direction from the post nearest the engine block is: 6-2-4-1-5-3. (to the left side of the number 6 post, there should be a hold down screw or strap for fastening the distributor cap to the distributor.

For a picture diagram, please go to this website:

Dec 27, 2009 | 1995 Jeep Cherokee

1 Answer

Spark plug wire position on distributor cap

ALL Jeep 4.0 motors use this firing order. Any year, any model, high output or not.

Also, the spark plug wire placement on the cap, in a clockwise direction from the post nearest the engine block is: 6-2-4-1-5-3.(to the left side of the number 6 post, there should be a hold downscrew or strap for fastening the distributor cap to the distributor.
For a picture diagram, please go to this website:

Good luck (rated this help)

Sep 06, 2009 | 1997 Jeep Grand Cherokee

1 Answer

1993 jeep cherokee. Can't get spark out of coil.

Check the Crankshaft Position sensor. Usually it will reveal itself through the check engine codes. If this is faulty, the coil will not get the signal it needs to fire.

Jun 27, 2009 | 1994 Jeep Grand Cherokee

Not finding what you are looking for?
Cars & Trucks Logo

385 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jeep Experts


Level 3 Expert

83481 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22393 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6927 Answers

Are you a Jeep Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides