hoopdaddy6

Oh, one more quick note: When it runs in the garage (3 car garage, all doors open) after about 3-5 minutes the exhaust makes my eyes feel like they are being burned out of their sockets. Have to shut it off, air out the garage, and step outside for fresh air.

Would this be due to the air fuel ratio being so far off?

5-90

That's what I was talking about when I mentioned cementing that line to the TB - the upper hole is blind, and no hose goes into it. That is the hole/bung you put the RTV in to stick the thing together.

Have you changed the MAP sensor? It's a standard GM part of the vintage.

The idle is theoretically not user adjustable (and I haven't figured out a way to do it - but I haven't really worked on it.) Check and clean your IAC - it's on the front of the Tbody, next to the TPS. I most often end up just removing the throttle body at intervals and cleaning the whole thing with a toothbrush and acetone - just don't get the TPS wet with anything! The only maintenance it really needs is a check of adjustment when you put the throttle body back on. You can remove the IAC and clean it (do not pull on the pintle!) and its seat, since that's what causes a lot of strange idle problems.

Check for vacuum leaks (as I may have mentioned) at the juncture between the head and the manifolds - particularly at the rear.

Also, check the resistance of the ground strap between the cylinder head and the firewall - if it's more than about two ohms, replace it. That strap forms the ground loop between the engine and the chassis, which forms the "zero reference" for the ECU and sensors. If it's shonky, your ECU won't know where it's starting from, as far as signals go. Adding an auxiliary ground from the battery to the chassis never goes awry - use at least an 8AWG wire, and clean the contact patch on the chassis down to bare metal. Using a sheetmetal screw to attach the cable to the chassis is sufficient.

Those are my first thoughts on the matter. Oh - and check adjustment of your TPS - you can find out how by searching here or at NAXJA. If you can't, ask again and I'll get it out of the FSM (which I need to issue as a writeup anyhow on my site, one of these days...)

hoopdaddy6

Ok, so I finally got together with my OBD1/OBD2 scanner friend at work. As I suspected, we can't connect anywhere. I hate to say it, but I am really beginning to hate this renix setup.

Where do I turn next? Would a dealership have a scan tool for the renix motors? I need to get this timing right, and slow down the idle.

Two things that don't make sense here:
1. Idle is better with the vac line disconnected from the MAP sensor, and new MAP does the same thing.
2. Why would they put all of this equipment in a vehicle if it is useless? This should NOT be this difficult!

PK'S XJ

Here is some advice another member gave me. After replacing the O2 sensor disconnect the battery cable for an hour or so. This will reset the computer so it can relearn how it should be running. What can it hurt to try???

5-90

1) The dealership may have the RENIX scan tool, but it's really not needed (as I mentioned before, RENIX does not store or throw codes - all it gives you is realtime data. You can get most of it with a DMM anyhow.)

2) It's not useless - there's just something wrong. I've hit my head on OBD just as badly, if not worse.

Go to Pirate and get the RENIX FI manual in the tech section. Also, pillage around and see if wiring diagrams are up anywhere (I may have them up at RENIXPower - I'm not sure) so you can track things back to the ECU.

Check to make sure the MAP is getting a +5VDC signal. That's a nominal value, so you're really going to check to see what voltage is coming out of the ECU, and it should be very close to the voltage going into the MAP. I don't have a pressure/resistance or pressure/voltage curve for the MAP yet (you can probably find one pillaging around on GM boards - I just haven't done it yet,) but that would allow you to check sensor response.

I'm fairly sure I mentioned that RENIX is pre-OBD, and that OBD scanners will not work with RENIX. Period. The technology is too different - OBD relies upon thrown codes, and RENIX doesn't throw any. But, it's really not that hard to work with, once you realise what you're working with (the advantage comes in learning to do your own thinking, instead of letting OBD do the thinking for you.)

Where are you? There are a few self-trained RENIX "experts" scattered through the country, perhaps you are close to one?

hoopdaddy6

Thanks again 5-90. I might be getting somewhere with this... After I gave up on any sort of diagnostic data, I started pulling things apart and troubleshooting. I am fairly sure the MAP sensor is working fine, as well as all of the vacuum lines, and electrical plugs, connectors etc. Also I checked resistance on the ground strap you were talking about. All checks out good, but still the idle issues.

Got it. I pulled the air intake duct off the throttle body to make sure the TPS wasn't keeping the TB opened up. Then I stuck my finger in the hole that feeds air to the IAC, and suddenly the clouds opened up and god shined his light down upon my and my jeep. With the hole about 90% closed off, my jeep has never been happier. I temporarially patched it up with some electrical tape, and drove it around town for a good 30-45 minutes. It has never run better.

So... correct me if I am going the wrong direction here, but did I replace the old IAC with yet another broken one? It seems like this thing is stuck open and letting too much air in, hence increasing idle and fuel ratio. The plan now is to sling a few more pizzas, save up another nights tips, and pick up a brand new IAC for $55 this week.

I am in Longmont, Colorado 5-90. If for nothing else, I am always looking for others to hit the trails with.

5-90

Or just remove the throttle body, take it to bits, and clean it. I've seen cases where a shonky idle is caused by buildup in the area of the IAC pintle and/or the throttle blade, so give it a good scrubbing with acetone and a toothbrush.

You'll need a new gasket (natch,) and don't get the TPS wet.