Ok, so I'm starting a new thread so that all the information is packed into the first post. Seems most people dont read big long threads.

I can't start my 90 Cherokee Laredo I6. I've replaced the following and done these procedures:

New fuel pump
New fuel filter
New CPS
New Idle Air Controller
Tuned the TPS
Checked all vacuum and electrical connections
Cleaned the throttle body
Replaced Air Filter
Replaced distributor (including cam sensor and gear)
Reindexed the distributor (brought crank to TDC on 1 compression stroke and reseated the distributor according to the FSM)

I have spark from the coil to the distributor, and from the distributor to the plugs. The plugs appear to be fine.

I am getting good pressure (around 35-40psi) in the fuel rail.

The cylinders have the following compression
1-116psi
2-118
3-110
4-110
5-120
6-123

Everything checks out fair except when I pulled the fuel rail. none of the injectors are spitting any fuel. Not a single drop from ANY injector but the fuel rail does have good pressure as noted before.

It seems that something is not allowing the injectors to spit fuel, whether it's the ECM or something else I can't figure out. I'm about broke now, even the junk yard looks expensive.

What the hell could be going on?

 

first, relieve your fuel pressure on the fuel rail then, turn the key to the on position so the door buzzes when open, and then push the bleed valve on the fuel rail for 2 sec, to make sure you have addaquite pressure for crank. if you have good pressure then only thing i can think is a failed ECU. you can probably pick one up from a junkyard for 100 bucks. sorry about the bad news.

 

Did all that...I'm leaning toward it being the ECU, but doesnt it also control spark? I would think if the ECU is toast, then I wouldn't have spark, or at least something else would be broken.

 

this applies to the renix engine..... http://www.lunghd.com/Tech_Articles/...iagnostics.htm
...here for refurb ecu.... http://www.wfaw.net/index_files/gif_13.html ...click "Auto Computer Exchange" icon at top right

 

Did you check to see if you have "keyon" power to the injectors? The ecu provides the ground for each injector, but that won't do a hill of beans if battery voltage is not there first

 

How would I go about testing that? I figure a volt meter, but from where to where?

 

It sounds like your Renix computer isn't telling your injectors to squirt, maybe because it is fried or because it doesn't know when to because it is getting a weak or intermittent signal from your CPS. Clean the CPS's grounds, on the bellhousing as well, and check for continuity or resistance with an Ohm meter. 87-90 is notorious for having bad grounds, so if you haven't done so already, clean and secure them.

If you can get a multimeter from Radio Shack or wherever you'll be able to troubleshoot a variety of Renix issues. Something that can test voltage, amperage, and resistance. You're looking for a very low resistance between one ground and another, in this case.

 

It's not the ECM. The CPS is new and the OHM reading on it is good. I went around and checked the grounds, the 2 that I know of. 1 on the tranny dipstick and the other on the firewall.

Anyway I replaced the ECM with the same model from an 89 and replaced all the injectors with the Dodge Neon '703's with the 4 pintles. Figured while I was at the JY I can grab those too (and they let me have them free, something good out of all this . Still not squirting.

I've got a good analog meter that does volts, ams, and ohms.

I may try soldering the cps connections together.

Also, the CTS and Knock sensor are disconnected I noticed. (I think its the CTS, real close to the knock sensor.) I know life goes on with a busted knock sensor, but will it freak if it doesn't have the coolant temp sensor?

One of the injector plugs was bad, the insulation on both wires was gone, I replaced it. I wondered if I can put my meter on the exposed portion of the wires to test voltage on the key-on like ***** was talking about.

 

Well, I got it started. I hard wired the CPS and cleaned the camshaft sensor plug. It turns over but it idles like ****. When I pust gas on it, doesn't improve, infact it wants to die more. I can let it sit idling and it will eventually die. But it's just this bluh, bluh, bluh, bluh, bluh. I guess it sounds like 1 or more cylinders is misfiring, but that's impossible. I've got the distro indexed exactly as it should and it's not skipping gears on the camshaft gear.

When I pulled the plugs to do the compression test they didn't look too bad. WTF now?

 

checkout the fuel regulator

 

Why the regulator? I'm getting plenty of pressure and the injectors are now firing. In fact, I set the valve cover on fire there for a minute testing...hehehe...It was a great start to the 4th! No harm though, I got it out within seconds and nothing burned.

I'll look for ways to test, I put my pressure gauge on it and seemed alright at around 35-40psi, but maybe theres more to it.

Thanks for your help!

 

FIXED! The CPS sensor I bought was defective. Replaced it again and good to go.

and I can already tell the Neon '703 injectors rock.

Thanks everyone!