WinALDL newbie needs help.

[jgr]

I'm brand new to WinALDL and I need some help reading the output. I've attached the log files and would greatly appreciate a second opinion.

I'm trying to pinpoint why my 90 K5 is idling rough & eradically. It also takes about 4 seconds of cranking to get it started when it's cold. It's been completely tuned up, checked for vac leaks, and has the following new parts: Distributer, IAC, MAP, TPS, TB gasket.

WinALDL is giving me a steady "CLOSED Loop Flag", "Old High Gear Flag" & "BLM Enabled Flag". I also get intermittent "Rich Flag" and "DRP Occured".

My coolant temp is running about 182 degrees but I thought this engine used a 195 degree thermostat. Is this the source of my problem?

Thank you much.

Jon

 

[4X4HIGH]

You should zip the file with winzip and send it to Brian at [email protected]. I just sent him a file an hour ago and he already got back to me.

I had sent him a file zipped with winrar a while back and he ask for it to be zipped with winzip.

 

[dyeager535]

Coolant temp should not be an issue. No matter the temp, idle should be smooth. You may have a 182* stat in there, what does it do as you drive it? Diff between 182 and 195 could be an acceptable variation in a sensor or t-stat, but if it's consistent at 182, the stat may be a 180*. Not a real problem, but it doesn't help anything like mileage.

DRP is distributor reference pulse, tells the ECM the ignition is firing the plugs.

Your crank sounds like the fuel pump relay, does it cycle the pump when the engine has not been run and you turn the key to run, not start? If not, does the pump run when you put 12V to the pigtail hanging off the fuel pump relay connector? And if the pump runs then, does the engine start faster with the 12V hooked up?

 

[jgr]

185 is the highest I've ever seen the coolant temp reach. That was at full operating temp while climing a hill. I'll have to pull the themostat and check it.

I can hear the fuel pump run when I turn the key on (w/o starting). I checked the relay pig tail and it never gets 12 volts and my multimeter does go off the scale each time I hear the relay 'click'; a few seconds after turning the key on. Just to be sure I have the right one: located at the top of the firewall next to the distributer cap on the passengers side, the red wire (the only loose wire). I dont want to put 12v to the wrong part.

Any idea what the Old High Gear Flag is?

Thank you.

 

[dyeager535]

Can't recall what high gear flag is. I don't think I'd worry about it, the ECM doesn't monitor gears AFAIK.

Someone with TBI is going to have to answer you about the relay being correct or not, I am nowhere near my truck (which I just got BTW) to check. AFAIK there is only one red wire hanging off of any relay in these trucks, and if that is given 12V, the fuel pump should run. But if you hear the pump prime when you turn the key to run, something else is going on.

If you have a fuel pressure tester already, I'd try that, but if not, you can remove the air cleaner, have someone crank the engine, and see if it's getting fuel spray before it actually starts. Obviously have to be careful doing this, but about the only way to know if the injectors are spraying fuel when it's cranking, short of a fuel pressure checker.

 

[Thunder]

Check you EGR / Egr solenoid. Try un pluging the vac line to EGR first. It it idles better the EGR solenoid is bad. If still idles rough pull the EGR and clean it. Check to see if it is stuck open.

 

[jgr]

No joy yet. My theory: The T-stat needs to be replaced so that the engine runs at the correct temp so then the computer will give it less fuel. The ALDL rich flag might be caused by excessive fuel vapor being sucked in via the PCV? The EGR/EGR solenoid needs fixing and this would correct the rough running at idle/part throttle.

I pulled the EGR valve, cleaned it, and tested it with a vacuum gage. It seems ok, but I can't seems to get the EGR valve to work when I apply a vacuum to it while the engine is running. It'll lift for a second and go right back down. What's up with that?

I also noticed that the engine runs really bad when the throttle is opened just a crack. I can see the EGR valve flutter, ALDL BLM goes to 114, and I start getting knock counts.

I replaced the coolant temp sensor (by the T-Stat) but it still runs at 180 degrees.

Suggestions welcome...

 

[4X4HIGH]

EGR valves in the later model trucks (90 blazer) are reverse back pressure type and can't be checked conventionally like the older EGR valves could.

 

[jgr]

I don't understand what you mean. Perhaps someone (not me of course) put the wrong EGR valve on this truck b/c I was able to take a vacuum pump to it and get the valve to lift almost immediately. It was fully open at 10" of Hg and it held at that vacuum.

 

[4X4HIGH]

I don't understand what you mean. Perhaps someone (not me of course) put the wrong EGR valve on this truck b/c I was able to take a vacuum pump to it and get the valve to lift almost immediately. It was fully open at 10" of Hg and it held at that vacuum.

If you can do just as you said (vacuum pump will move diaphram) then it's the wrong EGR valve for that year.