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87 XJ no spark

cps tests good.

My ground strap from rear of intake(?) to the firewall is not connected. I 'wedged' it tight, and still no spark. I will connect it, does anything else connect with it?

Have power to the coil. Coil tested good previously, but I will check again. Can I try a different type of coil? I have a couple canister coils, and some ford e-core coils.
 
Nevermind the coils for now except to do the ICM/coil refreshing in the link in my signature. Get a ground from the head to firewall!! Read about the ground refreshing in the same link.
 
got halfway through your renix thread right now. Got a big list of stuff to try. Gonna go take a break, then finish your thread, and my list. :)

Thanks for your help.

If I can't get it workin, you wanna come down and buy it? I'm south of Tucson
 
pleontks said:
got halfway through your renix thread right now. Got a big list of stuff to try. Gonna go take a break, then finish your thread, and my list. :)

Thanks for your help.

If I can't get it workin, you wanna come down and buy it? I'm south of Tucson
Click to expand...

Nah. No more projects. Just got my stroker built. We'll git r done.
 
pleontks said:
did dry comp test. All cylinders were within 55-71 psi. Other than lowness, nothing else significant revealed.

Put on brand new cps. Still no spark. Gonna go test cps and look at the grounds.
Click to expand...

Did you mean 151 to 171 psi? 71 psi is way to low, that is a blown head gasket or valves or worse across the entire head!

IIRC the maximum variation allowed between adjacent cylinders is about 20-25 psi.
 
No, I meant the lowest reading was around 55, and the highest reading about 71 psi.

cyl 1 - 62psi
cyl 2 - 70 psi
cyl 3 - 55 psi
cyl 4 - 71 psi
cyl 5 - 60 psi
cyl 6 - 52 psi

Those were the dry results. I did wet test on cyl 3, which raised the psi about 5. Did not do wet test on other cylinders, as the dry test was so discouraging.

ecomike...you got a link to your deisel swap? That sounds like a good read.
 
pleontks said:
No, I meant the lowest reading was around 55, and the highest reading about 71 psi.

cyl 1 - 62psi
cyl 2 - 70 psi
cyl 3 - 55 psi
cyl 4 - 71 psi
cyl 5 - 60 psi
cyl 6 - 52 psi

Those were the dry results. I did wet test on cyl 3, which raised the psi about 5. Did not do wet test on other cylinders, as the dry test was so discouraging.

ecomike...you got a link to your deisel swap? That sounds like a good read.
Click to expand...

Might check it with another gauge. Or, it's absolute toast.....
 
cruiser54 said:
Might check it with another gauge. Or, it's absolute toast.....
Click to expand...


That's kinda the diagnosis I was expecting. I asked one buddy, and he said that the lowness was probablly because it hadn't ran in who knows how long, and it'd probably go back up after running it a bit.

I'll see if I have another gauge, or I'll try my gauge on another engine, and see how that goes.

It was free, so I'd like to drive it, but I'm more into the FSJs (got a 76 j10 and a 77 cherokee).

Would it be worth putting the fuel injection on my 74 Gremlin 258 (have 4.0 heads, but not yet installed) or is it tied in with the ignition system?
 
I am wondering what would cause all 6 cyl to get so low in pressure all at the same time. I don't think that is enough pressure to get anything but an occasional miss fire, if it fires (combustion) at all.

Try a new gauge and put 1 tablespoon of oil in each cyl first and retest. Is the battery weak, does it crank at normal speed?

I wonder if some one did a poor head gasket swap, and the surfaces were not clean and flat. Is there oil the coolant or coolant in the oil?

Jeep fuel injection is operated by the ECU computer and sensor network, yes. It is all electronic.

I did not do the original Nissan SD-22 diesel swap, I took it over, bought it wholesale dirt cheap, it had lots of repairs and issues still that I had to figure out the hard way and fix. So I do not do a thread on it. There are threads scattered here and on the Nissan site from debugging issues one at a time since 2002. Some photos are in a 2006 (IIRC) thread in the MOD forum here. It was a 2.5 L gas Cherokee, 1985. The engine and 5 speed transmission are Nissan from a 1981-82 720 pick up truck. 2 WD, about 34 mpgs.
 
Battery is NOT fully charged. hehe. Battery is totally dead, and holds no charge. I jump it from my truck. XJ harness reads 13.5v (or so) when hooked up with jumper cables.

Starter turns crazy slow. Knew I'd have to do a different battery to get it to start, just wanted to verify spark first. First thing I will do is try with a good battery.

Did a tbsp of oil in cyl 3, raised it by 5 psi.

No coolant/oil mixing.

When I got it, it was from a youth retreat. They said it belonged to someone that used to work there. They'd never seen it run. What I think happened, is the mexican's probably ditched it, and that guy found it. This close to the border, we get a decent amount of ditched cars from the smugglers, and this place was at the end of a super long dirt road.
 
If the cranking voltage is below 10 V, which I am sure it is from your post, the starter turns way too slow and the Renix ECU will not see a high enough CPS voltage and WILL NOT SPARK, and will not start!!! The stock cables are barley large enough new, and adding the jumper cables means the voltage at the starter is probably dropping to 6 volts while cranking. NO way it will spark or run in that case!!

It also may may be turning too slow to show the true compression, as the rings may be loosing compression faster than it can turn over. Try a new battery and good clean posts and clamps and grounds, like at the oil dip stick, remove and clean the contacts to bare metal at the engine block near the oil dip stick, and clean the starter solenoid + cable contacts. It may fire right up!!!

The 87-90 jeeps are notorious for bad grounds causing no starts, and running issues, so clean both ends of the battery wires at the starter, engine block ground and NEW battery, clamps and posts.
 
Well, I put in the good battery, sprayed some carb cleaner in the intake, and re-ducttaped the hose with the hole, and SHE RUNS!

Poorly, and without brakes, but running none the less. Next two days are days off (mostly) so will do another comp test.

I appreciate ya'll's help. I will have more problems, I'm sure, as I get this thing up and going.

Is there anything special you have to do for filling the coolant on these? Lost some when I took out front 2 spark plugs.

I will go ahead and take care of the grounding issues, and the coil connection. And test the TPS. And do the fluids/filters. And spark plugs. Anything else I should do?
 
Clean the sensor male-female contacts, and check the ground on the harness side of the sensor with an ohm meter. Ask Cruiser54 for the ground sensor fix write up he did. The harness has a bunch of loose crimped piggy backed ground connections that cause wandering idles, high idles...
If the compression does not get up to about 120 psi or higher try some 20W50 dyno (not synthetic) motor oil next. Some marvel mystery oil can held free up stuck piston rings...

Check all the vacuum lines, air filter, and then make sure the rear CCV vacuum line on the rear of the valve cover is clean, or replace it. Check the vacuum line from the throttle body to MAP sensor, make sure it is not loose or leaking vacuum, it is critical to smooth engine operation.

Have you cleaned the throttle body, or IAC valve and port yet? Also you have an EGR valve, so it needs to be tested for sticky, or stuck operation at some point.

The 87-90 closed cooling system is notorious for trapping air in the top of the radiator, and it has only one exit, the curved upper radiator hose, so I try to elevate that hose by disconnecting it from the T-stat, then I also open the heater core heater hose that is also connected to the water pump outlet, to let air into the block, so the coolant can flow and displace air, I also elevate that hose, then I top off the radiator with the upper hose.

Also find the fuel rail, on the front of the fuel rail is a fuel pressure regulator, with a vacuum line. Pull the vacuum line, and if there is gas there, the regulator is bad and will cause stalling and flooding.
 
Last edited:
So, I connectedthe ground strap at the rear of the head to the firewall.

did the ground test. seemed alright.

Adjusted the TPS. Was about 1v low.

fuel pressure regulator good.

Vac line to MAP sensor good.

CCV vacuum line is full of crap.

What's next? Runs pretty good, but seems like there's a vac leak somewhere. Couldn't find one, though.

Still need to fill radiator and get some sort of matching tires before drivin it. And vacuum all the rat poop out.
 
CCV hoses/tubing needs to be in good shape. Have you sprayed around the intake with throttle body cleaner? If there's a vacuum leak there, it will show up when it's hit by the TB cleaner.
 
Yes.

Renix Vacuum Harnesses
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting, and is called the front harness, is Napa part number BK 715-1367
　
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151367_0269070623
　
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151366_0269070622
　
The tube from the rear of the valve cover to the intake manifold is part number 715-1365.
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_7151365_0066877355
　
Revised 09-11-2012
 
None of those links work.
 
Cruiser, do you have like an entire hard drive full of write ups and tips /tricks on hand for everything lol
You always seem toto have some secret hidden kernel of wisdom tucked away for every situation.........kinda spooky
 
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