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2000 no start after swap, and a few codes

T

tommy54

NAXJA Forum User
Location
Wisconsin
I swapped a 1990 bottom end with a 94 head into a 2000 cherokee, and used all accessories and flywheel from the 2000.
I can't get it to run now, and have pulled a few codes: p0700(trans control system MIC request), p1687(no mechanical instrument cluster bus message), and p1698(No CCD from TCM).
After replacing the engine the engine was hesitant to start, then fired for a couple seconds, then no start again. I noticed that the fuel and volt gauges weren't working, found those to be symptoms of a bad CPS, and replaced that. Now it doesn't even try to fire. Starter motor will spin, but nothing that sounds like the engine is firing.

-I have good spark
-Cam sensor is aligned properly
-I have compression
-Plenty of fuel at fuel rail
-Checked all grounds that were disconnected for swap, and inspected harness for pinched wires.

I hooked up a scan tool to pull these codes, but I tried to read the TCM and it tells me that it can't communicate with it. Am I doing something wrong with the code reader?
Will these codes cause a no start condition even though I have spark?
 
Well, I cleared the codes and tried to start it again. No start, but the codes didn't show up again either. Maybe those were from the old CPS.
 
If the ECU was disconnected from 12 volts for an extended period of time, the idle settings got deleted. You will have to use the gas pedal to start and keep it running for a few minutes until the ECU re-learns the idle.
 
I tried a little bit of gas pedal, and a lot of gas pedal. Nothing is working. I pulled all the plugs, and they're not soaked. I dried them off and put them back in to start over, I also disconnected the battery again.
The only thing I can think of is the cam sensor timing, but I thought that it didn't affect the spark timing. Thing is, I don't see how the cam sensor timing could be off. I know for a fact the engine was on TDC, used the toothpick method and dropped it in with the plug facing the firewall.
 
Then it's back to basics. Inspect all fuses and relays. Go over all your work, inspect for loose wire connectors, corroded wires/connectors, non-connected ground wires, damaged wires or wire connectors, and short or open circuits.

If the toothpicks fits, the Cam sensor is installed correctly.

The Crankshaft Position Sensor (CPS) can get damaged during engine swaps. Test the CPS and test the magnetic Camshaft Pickup sensor.
 
I've tested for spark, and I have it. Wouldn't a faulty CPS cause it not to spark? It is a new CPS. The toothpick fits, and still fits after turning the motor over multiple times.
I've connected extra grounds, one from the firewall to the block, and one from the coil rail to the battery ground. I've tested every ground in the system for continuity.
The old motor ran with a blown up cylinder, so I don't think the gas is the culprit. It's been less than a month since it ran with the old motor.
I've gone over every harness connection that I can find.
I've gotten seized up motors to run, so this is really messing with me. Spark, fuel and air, and it all seems to be in time.
 
Some possibilites are...

Bad fuel
Flooded engine and or air restriction
poor compression
weak spark

Last thread I read that had the same symptons your describing, they changed the coil and it fixed the problem... apparently they had spark too, but it was a weak spark... not a strong snapping blue spark.
 
Did you check that the injectors are firing with a Noid Light ?

Like Q said, if you have fuel, air, and spark, check the quality of the spark. Will it run on starting fluid ?
 
I can't even get it to start on starting fluid. I started the swap about a month ago, and the gas was OK then. The old motor ran with that gas and a blown up cylinder.
I am using a bottom end that sat around for a couple years, so I figure the compression won't be perfect right away.
 
Anybody have any ideas? I am really lost. Compression is around 100 psi right now, I assume it will improve after running for a bit. That should be enough compression to get it to start, right?
I have air, compression(ruling out valve timing), spark, and fuel(at least in the form of starting fluid), so the only thing left would be spark timing. The only things that affects spark timing are the CPS, flex plate, and computer, correct?
- I have a brand new CPS, and no other symptoms of a faulty CPS
-Flexplate looked fine, and only bolts up in the proper orientation
-CPU should be fine, as everything else seems to check out.
Any clues? I've never had an engine that I couldn't find a problem with, but wouldn't run.
 
Should run on 100 psi, (thats pretty low though)

Step back from it and shoot back to the basics. You only need 4 things. Spark, Compression, Fuel, and Timing. Which are you missing?
 
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I'm hoping that the 100psi jumps up a bit after the rings work there way around a bit and the valves do there thing for a while.
As far as what is missing, timing I believe, but since there is no distributor or plug wires, it's hard to figure out. I don't know how to make sure that the spark is happening at the right time without an O-scope.
I've been testing every sensor I can to make sure the ECU isn't trying to compensate for a sensor that is bad.
 
I seem to have intermittent spark at cylinders 3 & 6. Are these run by the same coil in the coil pack? I know that each coil runs a pair of cylinders, but I don't know how they are paired.
 
Thanks Mcque, that settles it. My coil rail is fine. Also ruled out fuel pressure, injectors, TPS, CTS, MAT, and cam sensor.
Tried moving the cam sensor out of alignment, got a few hiccups but nothing solid.
I pulled the coil rail, put plugs back in the rail, grounded each one with a jumper wire, and watched the spark on all 6 cylinders firing nice and blue. Compression is up to 100 on all cylinders now, and I expect it to go up once its running.
The only thing left is spark timing, and I don't know how to make it change. Man I wish I had a regular old distributor.
 
What is your fuel pressure exactly? Just because you have fuel at the rail doesn't mean you have good pressure. Have you looked at the pressure while cranking?

It is possible you got a bad new CPS.

How are you installing the cam sensor drive? Bringing the #1 to TDC on the compression stroke then installing the drive?
 
Fuel pressure spikes to 50 when cranking, then drops to 45 and stays there after the key is turned off.
Since the motor sort of ran with the blown up cylinder, I tried the old crank sensor. The old crank sensor no longer exhibits the symptoms of a bad sensor(no bus message, volt and fuel gauge dead). I have spark with both the new and old crank sensor, and have gone back and forth a couple times.
I brought the motor to TDC on compression stroke(easy to tell when valve cover is off), put in the toothpick, and dropped it in so the plug faces the firewall. Also tried one spline to each side of straight back. I also put it in 180 out just to see if it would work. I've tried leaving it loose and moving it slightly while cranking, and it seems to help if I move it clockwise, at least it pops on a couple cylinders, but not enough to fire up.
 
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