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86 2.8L wont start it turnsover but it wont start

B

black86xj

NAXJA Forum User
Location
roseburg, OR
maybe someone can help me out I replace the rotor, cap pickup coil, coil, spark plugs, spark plug wires. i dont know what else to check, i need help what else i can do thank you. oh i also change the pos and neg bat cables and the module.
 
Without knowing more about the condition of the truck, it's hard to guess. My first guess=

It probably needs carb work. I had one of those and it would only start if I held one of the carb plates open with a screwdriver.
If you haven't already checked the compression of each cylinder, do that. If they are all in spec for that motor, look for a carb rebuild kit. Clean out the carb and reassemble with the new parts.
It finally ran after doing the standard cap/wires. Turned out to have a cracked block. I don't mean to discourage you or to say that your motor has a similar problem. Simply sharing my experience with the '86 2.8 V6. I haven't heard many good things about them, but maybe yours is still good. If not, you can always give it a 4.0...

Good luck
 
first it was running fine on day went 2 the store came out try to started crank it try to start and that was it did not start no more I just got a weber carb on it brand new, cause I thought that was the problem at first but still did not wanna start. thx
 
So let's get this straight. First off, it ran good to get to the strore. You came out and it wouldn't start. Then you put on rotor, cap, coil, spark plugs and wires, and then a non-stock Weber carburetor?

If this is true, please verify or clarify the situation.

Anyway, the first thing I would do is check the compression. No point in going further if you are under 100PSI or probably 120.

Then check for spark by holding a connected spark plug up to the block or head while somone cranks the motor with the key.

Then check for fuel smell in the carburetor.

Let us know the results of those three tests and we can take it from there.
 
winterbeater said:
So let's get this straight. First off, it ran good to get to the strore. You came out and it wouldn't start. Then you put on rotor, cap, coil, spark plugs and wires, and then a non-stock Weber carburetor?

If this is true, please verify or clarify the situation.

Anyway, the first thing I would do is check the compression. No point in going further if you are under 100PSI or probably 120.

Then check for spark by holding a connected spark plug up to the block or head while somone cranks the motor with the key.

Then check for fuel smell in the carburetor.

Let us know the results of those three tests and we can take it from there.
Click to expand...

EXACTLY!

Fuel, Air, Spark, Compression, all at the right time in the right place = running engine.

Someone (imagine a very LARGE finger pointing at YOU) has to determine what the missing piece(s) is (are).
 
4.0 wont fit in pre '87. The radiator support was moved forward (hood latch to the outside) and large notch put in the firewall to fit the 4.0) if the motor is toast he can replace it with a 3.4 or 3.8.
 
stephenspann27 said:
4.0 wont fit in pre '87. The radiator support was moved forward (hood latch to the outside) and large notch put in the firewall to fit the 4.0) if the motor is toast he can replace it with a 3.4 or 3.8.
Click to expand...

With a little work the 4.0 can fit in the pre-87 XJ, been done, plenty of info on this and other forums.
 
yeah pretty much thats wht happen one moment ran and then i didn't, ok thank you guys I will do the test and i will let you guys no watt is up thank you.
 
i tested 4 spark from the coil and the cap and I have spark it looks weak but i have spark and i have notice that the carb is spitting out gas, whats up with that. i got spark but still not getting it 2 start, i haven't got the chance to do the compression test yet.
 
With the spitting from the carb it sounds as if you have an open intake valve on the compression stroke.
 
black86xj said:
thank you i also found out that the timing chain was bad and jump timing and could this affect the compression?
Click to expand...

Absolutely! You have a cylinder with a moving piston and compression rings, air enters on the intake stroke and then is compressed as the piston rises on the compression stroke--both valves closed--and compresses the air. So, if the timing has jumped the relationship between the piston, crank, cam, and valves is going to be wrong so the piston is hitting TDC on the compression stroke but there is an open valve allowing the compressed air to shoot back out through the intake manifold and the carb.
 
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