Jump to content

starting issues (formerly buying advice)


Recommended Posts

Okay, hopefully looking at an MJ that has "no spark"... died on the guy going out the garage one day.

 

- battery cables

- ecu

- cps

- distributor possibly 180

 

Anything else to check on it? I hate buying things that don't start. :(

Link to comment
Share on other sites

My first XJ did the same thing in the middle of an intersection. Ended up being the ballast resistor.

If it's the ballast resistor, it'll have spark but no gas, and it should start while the fuel pump is bypassed and then die when the key is returned to the "run" position. The original post said "No spark." (Dunno if he meant that, but that's what he wrote.)

Link to comment
Share on other sites

I hate buying things that don't start. :(

 

I like buying things that don't start :D

 

I get them for alot better price :yes:

 

Yea, if the guy didn't mess with it, and it just quit, and has no spark, more than likely its the CPS.

 

You could "try" to unplug it, and plug the connect back in, Sometimes that works, or get an Ohms reading off the CPS, should read from 125-275 Ohms on terminals A & B. if your not in that range, the CPS is in need of replacement.

Link to comment
Share on other sites

Well guys, I tried today. I went to see it, and after discussing with the owner and coming to the conclusion that it most likely was the cps, I bought it.

 

Then I bought a new cps for it and taught myself how much fun it is to install one instead of coming back with a trailer. Got it installed, all pumped up, turned the key to crank it over and.....

 

It kept cranking. and there are no lights on the dash at all.

 

No clue. The owner didn`t do any work on it, just had a friend check it over, who said the ignition coil, fuel, plugs, distrib., ballast resistor, etc. were all fine or replaced. Then I found out that it when it was stolen once (which I knew), he had weird problems like the horn going off around corners. So maybe something is screwed in the wiring.

 

and where`s the ecu on these things?

Link to comment
Share on other sites

and where`s the ecu on these things?

If it's a Renix (1986 thru 1990) the ECU is under the dashboard, right over the driver's right foot.

 

There's a bunch of wires in/on the steering column. If they hot-wired it when they stole it (which is what usually happens), that's almost certainly the problem. Keep in mind that the key does NOT operate the ignition switch. The actual switch is down at the base of the steering column. The key operates a linkage rod, which in turn operates the actual switch. If either the key mechanism (not the lock cylinder itself, but the bits that the cylinder turns) or the operating rod got mangled, the rod may not be turning the switch on when you turn the key.

Link to comment
Share on other sites

Thanks Eagle. I forgot to mention that the steering wheel was replaced by a dealership, and the rig died before he could find out about the horn thing. Why he never took it back, I dunno.

 

anyway, he thinks maybe they screwed up the wiring when putting it in.

 

He`s not home tomorrow, and it is still at his place. He`s not around tomorrow, so next time I go back I`d like to make sure I have some good starting points (no pun intended).

Link to comment
Share on other sites

The whole steering column is idiot-proofed, basically... The plugs only fit one way. That is, if they changed the column. However...

 

Ever hot-wired a car? Probably not. Generally most older vehicles were all basically the same and not terribly hard to do. The standard method is to forcibly gain access to the back of the ignition switch (key switch) by tearing the column apart or tearing it out of the column. Some guys punch the lock in it, different story (I don't really know how that works anyways). From the back of the switch there is only 3 wires that actually matter (for the thief at least). The ground, the ignition on, and the crank wire. Maybe I'm getting too specific, but this is 'common knowledge' anyways, they take the ignition on wire and ground and twist them together, then touch the crank to that to crank until it fires.

 

Anyways, if lights/doodads aren't coming on when you put the key to the 'ON' position, I would assume that the dealer screwed up repairing the ignition on wire that was torn/cut. Part of the issue is that sometimes the thief isn't terribly successful in that when they tore the wires, they might have broke them off the switch and ALSO, off the plug at the base of the column.

 

You can bypass the ignition switch and wiring in the column, by pulling one of the plugs at the base of the column and jumping the pins on the plug. I'd have too look at either a Jeep or older GM product or my E manual to tell you which...

Link to comment
Share on other sites

Can you hear the fuel pump running on these things when you turn the key on?

 

 

Normally. Lots of them are bloody loud. With the door open you should be able to for sure.

But "listen fast." If the system is working, the pump stops once the rail comes up to pressure. That may take from two to five or six seconds, depending on how long the vehicle sat before you activated the fuel pump. When the pressure gets to where it should be the pump shuts off.

Link to comment
Share on other sites

Okay, I have it here and I can't hear the pump. The gauges don't move at all when I turn the key, even though the engine cranks. So, no longer think it is the fuel pump. I believe that when the key is turned, the starter is engaging, but the truck doesn't know the key is on.

 

Is that possible? ECU fried?

Link to comment
Share on other sites

What I said earlier... The wiring in the column or specifically to the ignition switch would be my first suspect. If nothing happens with the key in the 'on' position, you don't have power to anything. Normally the gauges will move to their happy place (voltage being the most obvious), the fuel pump will hum or hammer, and the stereo will come on, etc. Crank is an independent function of 'on' (or at least I recall it being with these, I'd have to check a wiring diagram to be 100% sure) and it can crank till the battery is dead with nothing else coming on (the EFI being the main issue there).

 

The ECU for the Renix is pretty bomb-proof. If it's fried, most likely it is because something was wired wrong and fried it. In which case simply replacing it won't be helping you at all. Besides, you'll get gauges and power to other things even if it is fried - it does nothing but control the engine.

 

Reading back (which I should have done earlier), Eagle states that the ignition switch and the key switch are separate and connected by a linkage. That had slipped my mind earlier. Regardless, that linkage may well not be working. You can bypass the linkage and switch by jumping some pins on one of the plugs - I'd tell you which but my 'E' manual is somewhere else right now...

Link to comment
Share on other sites

Ignition switch sounds likely, as I just bypassed the fuel pump via the pins in the relay section. Hummed great.

 

If it was a failed ignition switch, the engine would think it is turned off - even if the starter doesn't. That would explain why it died on the PO halfway out of the garage. And no matter what I do, it will continue to think it is turned off, right?

Link to comment
Share on other sites

and where`s the ecu on these things?

If it's a Renix (1986 thru 1990) the ECU is under the dashboard, right over the driver's right foot.

 

There's a bunch of wires in/on the steering column. If they hot-wired it when they stole it (which is what usually happens), that's almost certainly the problem. Keep in mind that the key does NOT operate the ignition switch. The actual switch is down at the base of the steering column. The key operates a linkage rod, which in turn operates the actual switch. If either the key mechanism (not the lock cylinder itself, but the bits that the cylinder turns) or the operating rod got mangled, the rod may not be turning the switch on when you turn the key.

 

 

Okay....so I'm under there. I should be seeing the rod move when I turn the key, right?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...