Hey guys, its been a real long time since I've posted anything on here. I totaled my blazer and haven't really had a reason since. Heres what i'm struggling with recently. My brother has a 1999 ZR2 Blazer with the 4.3l, it has had an engine swap done so I'm figuring this problem is somewhat related to that. The problem it's having is really hard starts from cold. When you first try you cannot give it any gas or it will immediately stall out. After a few minutes of trying to idle you have to rev it up about 10 times to about 3k rpms to get it running properly. Through this whole process it normally stalls out several times and misses/backfires a whole bunch. I went and got his engine codes read for him and they are as follows:

P1345 - i read on here that could be the distributor gear timing.
P0101 - can't remember what this one was but it didn't seem important to the starting problem
P0118 - Bad coolant temp sensor i believe

Also, after it is started and warmed up and everything it runs fine and doesn't stall out. However it does have some pretty bad throttle lag.

Let me know what you guys think please, any help is appreciated!

Thanks
Derek

 

BUMP BUMP come guys i could really use some help on this one

 

P0101 is the Mass Air Flow Sensor. P0118 is the engine coolant temp circuit high input. It can be caused by a bad sensor, rusty sensor, bad connections, bad/wrong coolant (causing everything to be gummed up).

I think your P0118 might be causing your P1345 as the ECT sensor provides info to the PCM which together with aggregate info can causing the timing to be off.

I would clean the MAF Sensor,air box, change the filter. If he has a K&N filter (or another brand) there is a theory that the oil on the filter can gum up the MAF sensor.

I would also pull the ECT sensor and either clean it up, or replace it (knowing me, I'd probably replace it). Make sure he is using the correct coolant (DexCool). He might want to consider flushing the system if the wrong coolant has ever been used. Matter of fact, I'd highly recommend it. Obviously replace the thermostat if wrong coolant used.

Clear all the codes, and have him do the drive-cycle. Link is somewhere on here.

Other things to consider. If he is not using the manufacturer recommended oil weight or has not done an oil change recently, the oil pressure fuel sensor could be turning the engine off because oil isn't getting where it needs to (too heavy and sludgy). This could indicate a problem with the oil filter bypass valve and I think an engine oil flush might solve that along with fresh oil and filter.

Well, that's my 2 cents. Hope it might help.

EDTI: P.S. While you're doing the other things, it wouldn't be a bad idea to also do a fuel leakdown test just in case.

 

Here's a link for the drive cycle test after you have cleared the codes. This will perform all the diagnostics to see if any codes re-appear.

General Motors Driving Cycle

 

Always diagnose & repair DTC's in the order they are retrieved, then clear the memories with a scan tool, then do the drive cycle to verify your repair and that no other DTC's are set.

P1345 means camshaft retard is off more than ~27 degrees. You can verify this on a capable scan tool. The most common reason is that the distributor is off at least one tooth.

 

So i got out and worked on it some today. I started off by checking the ECT sensor which gave me a good laugh when i found it to be unplugged...felt pretty stupid there. Then i started playing the the MAF sensor. Car ran like **** with it plugged in and ran fine with it unplugged....tried cleaning it first, didn't help so i got a new one. The car now runs fine from a cold start. I'm assuming that will take care of the P0101 and the P0118 codes.

However, i still believe there is a timing problem with the car. I was starting to look into the timing but couldn't get very far today before i ran out of energy and heat. Does anyone have the timing procedure for blazers? Will a timing light work or will i need to do something else? Since the engine has been replaced im not really putting anything out of mind but i don't think the timing chain is off a tooth because i would imagine it would run very poorly if that were the case. I wouldn't be surprised if the distributor were off a tooth like Captain Hook mentioned above.

 

Timing lights are obsolete on this engine. Ignition timing is viewed on a scan tool, and it is not adjustable. If the P1345 is displayed, it will exhibit symptoms similar to incorrect timing.

 

I kinda figured the timing light would be useless. What should i take as my next steps in your opinion?

 

If the P1345 is still in memory and the SES light is on, you can try moving the distributor one tooth. Without a scan tool to tell if it's advanced or retarded, you've got a 50/50 chance on which way to turn it.

 

Hey Captain...assuming he has not removed the distributor, it wouldn't be possible for it to move a tooth would it? Do you think the ECT being unplugged could have thrown the timing off some? I read that somewhere. Or is there no way that the ECT could throw off the timing be enough to display a P1345?

Of course, if the distributor has been removed at one time or another, that would probably be the answer.