no startie

[mjtjnj]

Hey guys,

The 87 was starting to run badly, sounded/felt like it was going on 3 (instead of 4 cylinders). I was driving it anyway, with the core 2.5 in the back going in for rebuild. I was waiting on Mopar's new 2.5 cam, which was "backordered" and now "cancelled (anyone know anything about this?)" Anyways, I didn't care it was running badly, it was getting a new engine. One day it wouldn't start at all. Cranks, but no start. Seems to be getting spark, but it looks weak(?). RENIX scares the hell out of me, so where to begin? Any sensor that would cause it to run crappy then not at all? What? All of them? LOL! :cheers:

 

 

Tom

[Pete M]

When was the last tuneup? It doesn't hurt to replace accessories since they will be going on the new block too.

[mjtjnj]

hey Pete-

 

not that long ago. Plugs, cap, rotor, wires. I'm pretty good about it. It just started losing power, not really missing or idling rough. I wasn't that concerned, but I figure I'd like it running when the swap is a go, so that I don't get a new block in there and have some electrical gremlin. O2 sensor is new. Probably will get a CPS and MAP sensor now rather than wait until the new engine is done. I know the CPS can prevent it from starting, and the TPS won't; what about MAP?

 

Thanks

Tom

[Eagle]

CPS.

 

Yes, the TBI 4-cyl uses the same CPS as the 4.0L, and it causes the same problems when it goes bad.

[mjtjnj]

CPS.

 

Yes, the TBI 4-cyl uses the same CPS as the 4.0L, and it causes the same problems when it goes bad.

 

That's where I'm starting. Just got it. Is it up high on the drivers' side bellhousing as well? I took a quick look up there and couldn't even see it. Gonna be a messy job, with all the oil under there! :eek: Any tips on getting it out/in???

 

Tom

 

:cheers:

[Wildman]

Yea.....find some one with super long skinny arms

 

:teehee:

 

Seriously.......I've changed a couple, and found taking off the transmission cross member at the frame and dropping the transmission (and T-case) works the best. Gives you better access to the CPS bolts, and you can see what your doing too.

 

That and a couple long extensions, and using magnetic inserts in the socket, so you DON'T drop a bolt into the bell housing.......that's real trouble there.

 

If you have a lot of oil on the under side of the engine / transmission, you might want to clean that off first.

 

If you go this route, when you drop the transmission, keep an eye on the fan blades so they don't hit the radiator.

 

I go this route, cause I got short fat arms :cry:

[mjtjnj]

OK, replaced the crank position sensor. Thanks for the tips on lowering the transfer case a bit, really made the job easy. Is there a way to put the thing in backwards?! :)

 

Pulled the 4th plug wire, hooked up the jumper cables, looks like a decent spark -- still no startie. Guess I should check for fuel next. Just pull off the inlet line and turn the key on - that's the right next step??

 

Thanks guys

Tom :nuts:

 

BTW in this picture, I installed the CPS with the part facing you in the picture towards the bellhousing.

 

[mjeff87]

Tom,

Fuel, air, spark, compression......

 

You have spark, and air (unless a family of squirrels have taken up residence inside the manifold :D ). I doubt you've lost compression, so that leads to fuel. Your pump may be supplying adequate pressure to the TB, but the injector may not be working. Verify fuel pressure to the TB, and if it checks out, suspect the TB wiring. Hook an analog meter to the two posts on the injector (back probe them) and have someone crank the engine...you should see the meter needle sweep back and forth, confirming voltage pulses to the injector. If not, you may have a break in the wiring to it.

 

Glad to see you're still around :cheers:

 

Jeff

[Eagle]

Got good spark? Take a cup of gasoline and dribble a bit into the throttle body, then try starting it. It's no different than a lawn mower -- you can start it and even keep it running by pouring gas right down the throat. Just be careful -- you don't want to be holding an open container of gasline over it if there's a backfire.

[mjtjnj]

Got good spark? Take a cup of gasoline and dribble a bit into the throttle body, then try starting it. It's no different than a lawn mower -- you can start it and even keep it running by pouring gas right down the throat. Just be careful -- you don't want to be holding an open container of gasline over it if there's a backfire.

 

Seemed like good spark. By the time I got around to cranking it, it was dark, so any spark looks good then. I did dribble some gas in there, no dice. Ran out of starting fluid, which I love. Have to get some more. I'll have to check the injector, thanks Jeff, after that.

 

I didn't really mind changing the CPS because I'd like all newish sensors when the rebuild is done, but I'm not sure that's why it didn't start in the first place. I had SOME spark, just not a GOOD spark, so I thought -- but it was daytime when I first checked. Bad CPS = no spark or poor spark?

 

:dunno:

[CrankShaftKid]

I had no spark early in the week on my 4.0L. Changed the coil, still no spark. Changed the cps and it fired right up. Seems like the CPS is the leading culprit for random no spark problems.

 

Also, if you can, pick up a timing light. That will take the guess work out of whether your getting spark or not.

[mjtjnj]

I had no spark early in the week on my 4.0L. Changed the coil, still no spark. Changed the cps and it fired right up. Seems like the CPS is the leading culprit for random no spark problems.

 

Also, if you can, pick up a timing light. That will take the guess work out of whether your getting spark or not.

 

I have one -- I'm definitely getting spark, just not sure if it's brisk enough for combustion. I'm going to chase down the fuel end of this for awhile.

[mjtjnj]

I had no spark early in the week on my 4.0L. Changed the coil, still no spark. Changed the cps and it fired right up. Seems like the CPS is the leading culprit for random no spark problems.

 

Also, if you can, pick up a timing light. That will take the guess work out of whether your getting spark or not.

 

I have one -- I'm definitely getting spark, just not sure if it's brisk enough for combustion. I'm going to chase down the fuel end of this for awhile.

[brigarpeon]

I have one -- I'm definitely getting spark, just not sure if it's brisk enough for combustion. I'm going to chase down the fuel end of this for awhile.

If it's a blue white spark it's enuff. If it's orange it's weak. You may have an ECM problem. Recently it seem to me that there's alot of "old" wiring problems surfacing... fusible links, relays burnt, coatings wearing through etc... Make sure all is well in the power side of things Latch key. fuel pump.

[mjtjnj]

I have one -- I'm definitely getting spark, just not sure if it's brisk enough for combustion. I'm going to chase down the fuel end of this for awhile.

If it's a blue white spark it's enuff. If it's orange it's weak. You may have an ECM problem. Recently it seem to me that there's alot of "old" wiring problems surfacing... fusible links, relays burnt, coatings wearing through etc... Make sure all is well in the power side of things Latch key. fuel pump.

 

Yeah, my plan is to disconnect the fuel line, turn the key on and see that gas comes out -- and not sludge LOL.

[mjtjnj]

Ok spent a little time with the non-moving MJ in the yard today. Neighbors want it started worse than me!

 

Unscrewed the fuel lines - the pump works. Looks like, after cranking, that the butterfly down the throat of the TB is wet with gas, too. So I'm getting fuel. Also getting blue spark. Fuel, air, spark. Check. Any ideas? :headpop:

[mvusse]

Timing? Or basically, has anyone ever done anything to the plug wires and possibly put them back on wrong?

[mjtjnj]

Timing? Or basically, has anyone ever done anything to the plug wires and possibly put them back on wrong?

 

Plug wires are ok. Gas had Stabil in it; timing shouldn't be off, unless the chain jumped a tooth or something, which at 187K miles, I guess is possible. What is the correct timing for the 2.5? Do I disconnect the distributor module to check it?

 

Thanks

Tom

[mvusse]

I don't think the timing is adjustable. I know it isn't in the 4.0. But yeah, never thought about the timing chain (or belt?). That might be worth checking. Place the engine at TDC, pull the distributor cap and see if it's pointing anywhere near #1.

[mjtjnj]

Whoops. I wasn't at TDC. Got it to TDC, and rotor was pointing between cylinders 2 + 3. The question is, can I pull the distributor out and put it back in in the proper orientation? I just want to be able to move this truck around.....any idea if that will work?

 

Thanks guys

 

:brows:

 

Tom

[mjtjnj]

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