egr 17087196 what replacement to use or none?

[ChevyTech]

If the Thermostat is to cold the system will run richer then with a 195 thermostat.

Also the system will not run many the self tests because running at operating temp is one of the criteria need before the ECM will do the tests. There could be several problems but the ECM will not set trouble codes because it never reaches the test criteria.

Also you have headers on it. Are they short headers with the o2 sensor within one foot of the exhaust port in the head?

Are you running a heated o2 sensor, or a one wire o2 sensor?

[benoit454]

its a one wire and it's in the collector of the shorty stainles header.

DDad said it ran great for him, maybe just a lil miss at idle or something on first start up when cold, but aint but like 60 or so in the mornings here or higher. he said it ran like new, no stalling and no hard miss at idle when warm and at a red light.

Only changes have been plate over the egr hole, and block the vac. line, which has been done for a week or more, the egr plate is new, and then the timing being set back was just the other day. The timing made the biggest difference for sure.

[benoit454]

it died, once on dad, stiil runs great, but he came home from work, pulled up to my driveway gates, dogs were out, threw it in reverse, back up, went to drive, didn;t get over far enough or something and went back to reverse and it died, started right back up this time, and he parked. Other then that he said it runs great.

I think I'mg going to bump the timing back a hair and tighten it down good, it may have advanced itself, it's not completely tight.

[ChevyTech]

If the truck dies there is a problem.

I can’t hear it to know how weak of an idle it has.

To go any farther toward helping you I need facts and numbers.

What PSI reading is the fuel pressure at with it running?

What is the timing set at in degrees?

Does it ever make it into closed loop operation?

What is the idle speed, and is the IAC controlling the idle?

What is the coolant temp with it running?

A photo of the O2 sensor position would help too.

[benoit454]

the o2 is in the same place as if it were in the stock manifold.

temp is around 195 or so, fuel pressure is like 12.5-13 running.

closed loop no idea, don't know how to tell if it is.

idle speed is like 800 in park and 600 in gear.

I'll have to check timing at some point, but that's going by the balancer and timing tab if they are correct.

[ChevyTech]

Well; you have a new distributor, it is idling fast enough, the fuel pressure is good, and it is getting to operating temp.

Does the IAC seem to do a smooth job of controlling the idle? When you put the transmission in gear does the speed hunt around a bit or sag a while before the IAC can get it controlled?

When you start it cold, does the idle slow down smoothly as it runs?

You might want to try unplugging the O2 sensor or something else and see if it is capable of setting trouble codes.

closed loop no idea, don't know how to tell if it is.

“Field Service” mode

Shows Open-closed loop

Jumpering A&B of the ALDL with the engine running enters the “Field Service” mode. In this mode the service engine soon light will indicate whether the system is in open or closed loop operation.

While the system is in the field service mode, new codes cannot be stored, and the closed loop timer is bypassed.

In open loop the service engine soon lamp flashes two and one-half times per second
In closed loop the lamp flashes once per second.

If the light stays off most of the time the system is running lean. If it stay on most the time it is running rich.

[benoit454]

oh so I'd jump it and drive or just let it run? I haven't done that.

As for iac I'll have to check that and see if it hunts around or goes right to where it should be.

I did unplug the collant temp sensor once with it off and the truck would not start, it flooded out, I plugged it back in and tried it, like to never got it going lol.

I could try unpluggin the o2 or something, should I do this with it running, just unhook it? or unhook with it off and start it?

[benoit454]

ok haven't done much, but here's a lil more info on what I found out...

I fired it up cold, this afternoon, started good, idle was up, and smooth, then as it started to drop off about 30 seconds or so after startup, it got rough, was like missing, after revving it up a couple times it smoothed out and was idleing good. I checked the idle in gear, it drops right down, then going back to neutral or park goes right back up, doesn't hunt for idle or anything.

[ChevyTech]

I could try unpluggin the o2 or something, should I do this with it running, just unhook it? or unhook with it off and start it?

Unhook it with the engine off, and make sure it will not fall against a hot part and get damaged when you drive it. Tape it to something if you need to. Drive the vehicle and it should set a code within a few minutes.

[benoit454]

would it do the same thing sitting in the driveway? just idleing or running?

[ChevyTech]

Originally Posted by benoit454

would it do the same thing sitting in the driveway? just idleing or running?

Here are specifications I pulled for a simular question, and I think they are from the 1993 C/K emissions manual.
Here are the criteria for the ECM to set a code 13:
Engine coolant temp above 158F,
At lest 2 minutes engine run time after start,
O2 sensor signal voltage steady,
Throttle position above idle (5%),
All the above conditions must be met for 60 seconds.

[benoit454]

ok good info to know then. I just woindered because usually the trucks gone during the day and I don't have much time to work on it. it be better to drive it because it take sforever usually to reach temp in the driveway esp. idle, so it be best to drive.

I'll have to check it out.