toka

RC Eng sent our injectors back - 2 were leaking internally. All 4 are spec'd with avg. 460cc. At least our Rx started after we put them in. Timing was way off -- thanks to Irv's post on the CAS, we found it was 180 degrees off. Now the car will idle, albeit roughly, at 1000-1100. Haven't been able to adjust it lower without it stalling. The car does backfire on deceleration now. In checking the pressure sensor, the reading we got was 2.8v (fully warmed engine). What's confusing is per the FSM, it's too high and per Haynes, it's too low. Which is which??? Is this sensor defective or what? Next thing to check is the TPS and if the pressure sensor is okay, add another ground to it. Also found that if we push in the AFM just a little, the engine smooths out but idles up to 2000. Couldn't find any vacuum leaks but think we have some kind of air flow problem. Any ideas???



1990 GXL non-turbo

HAILERS

That part about the pressure sensor caught my eye, where you say its too high. I'm only looking at the 88fsm located at http://www.iluvmyrx7.com section 4A(for N/A engines) and it says the reading should be 2.5-3.5v Now if I go to the section 4B(for turbo engines)it says 2.0-2.5v So it would appear that your looking at turbo specs when you should be looking at N/A specs in section 4A. Like I said, I'm reading 88fsm, your reading from a ???fsm. Its really funny. Section 4a(the N/A section) calls it a BOOST SENSOR, and section 4B, the turbo section calls it a PRESSURE SENSOR. On the whole the same animal, just configured internally different. If I may say so, I don't think you can set the timing until you get below that 1000-1100 figure, because the last time I looked, the ECU starts advancing the timing just about there. Are you really sure that the timing is spot on? Retorical question. The 88 manual has you putting a vacuum on the sensor. Is the 91 manual doing the same thing?

niner

always choose factory service manual over haynes. not sure on your other problems though. sorry

hanman

Food for thought.........
When installing a Atkins rebuilt in my 90 vert, I talked with David Atkins. He stated that the timing can be off as much as 5 degrees in the second gen cars. He said to set the timing right on the mark and then "swing the cas a little each way, and see if it idles a little better".
hanman

toka

Hailers, you're right about the sections In the 1990 FSM Section F1 is non-turbo and F2 is turbo. Guess which one I was looking at! So, according to F1 - Pressure Sensor - the reading should be 2.8-3.2V @ 100 mmHG, which we got a reading of 2.8V, so the pressure sensor checks out. On the timing issue, we couldn't even get it started at first. We lined up the timing marks, got it started but it wouldn't idle. The timing mark kept bouncing back and forth. According to Irv's post, we pulled out the CAS to see if it was inserted correctly. The marks weren't even lined up on the CAS. The dimple was 180 degrees from the arrow. When we lined this up and reinserted the CAS, we then adjusted the timing. The mark on the pulley stayed lined up and idle stayed at roughly 1000-1100, although it kept "popping", especially after deceleration.

We later checked the TPS according to Irv's post and the read out was 4.58V (warm engine). Irv stated it needs to read 1 +/- .2 V so we kept tightening it up until it would go no further, ending up with the readout at 1.2V. This doesn't seem right. ???

Also, what're your thoughts on the AFM? Oh, another MAJOR thing that is happening now is the car will not "go" - it does not have the power to take off. This wasn't happening before!!!! It's like it's not getting gas or enough air or both! We don't know what has happened!

HAILERS

Can't say about the tps. I have only 86/87 experience and they use a different tps. Can't relate. I'm writing this because I'm a bit of a worry wart. The timing....I'll put it this way. If I put a timing lite on my car at idle the marks line up just like they should because I set it right at some time, now if I slowly rev the engine with the timing lite on the marks, around 1000-1100 rpm I will see the timing advance(ECU causes this advance) by looking at the marks. What I am worrying about, probably without cause, is that you set the timing with the timing lilte at a very high rpm. This could have resulted in the timing being incorrect. When setting the timing(turning the cas until the marks line up with the pointer while using the timing lite) with your idle at 1100 rpm, I think, has resulted in your timing being off, maybe. You need to get that rpm down to a reasonable figure like 500-800 rpm, so the ECU will not have already advanced the timing, like it might have if you set it at 1100. We've got to get your idle down to a reasonable figure somehow so we can double check your timing. If you jump the initial set coupler, will the idle drop down some?