I'm not sure if anyone is gonna know the answer to this question but here goes. I have a 2005 blazer and ordered ac delco spark plug wires. They gave 9746kk ac delco spark plug wires. When I look them up it says it for a blazer up to 2004. Do you think that would be a problem to use on a 2005 ? I looked at parts geek and they have 4 different sets of ac delco wires for a 2005 blazer all different prices. I'm not sure why other then 2 of the sets have something to do with X in the vin and the price. I don't think because my wires are for a 2004 it's a big deal but I could be wrong ? When I look on Amazon it shows up to 2005 I'm confused. Here's the info from Amazon. 1998-2005. The only reason I'm asking this question is because of all the misfiring and problems I'm having and I was thinking it might be something really stupid !

 

It is a listing issue due to the fact that the vast majority of sales were to fleet services in '05, but they are the same truck as in '04.

 

I'm not sure what you mean my apologies. You say nothing changed so will they will be ok to use on my truck. So basically these other wires that parts geek are selling at different prices are the same and more money 🤔. I thought maybe the conductor's in the wire might be made from a different material or different gauge wire.

 

I changed my MAP sensor with a Chinese made one. How can a verify that it's working correctly ? I was watching the values on the scantool today and it's showing 41-42-43 kpa @ idle then started showing 39-40-41 kpa ? Would this be in spec ? Are cheap sensors ok or should I buy an ac delco/Delphi MAP sensor ?

 

A MAP sensor should read atmospheric at key on. Vacuum at idle is a loaded question because there is always the possibility of an erroneous sensor reading but vacuum level and behavior is a powerful diagnostic tool especially when the readings are not normal but accurate. Conventional wisdom is a steady idle vacuum of 14 - 22 inHg but when our engines are healthy its probably around 17-20. So one check is the reading at key on and at idle correlated to a quality vacuum gauge. Some guidelines on idle vacuum:

ENGINE STATE VACUUM GAUGE READING INDICATION
Steady idle (800-1200rpm) Gauge steady, 17-22 Normal & healthy
Steady idle (800-1200 rpm) Intermittently drops several needle divisions Sticking valve or broken valve spring
Steady idle (800-1200 rpm) Steady, low reading, 8-14 Small vacuum leak or valve timing off; could have low compression/worn rings (verify with a compression or leakdown test).
Steady idle (800-1200 rpm) Steady, low reading, under 8 Vacuum leak (check brake booster, vacuum lines, etc.)
Idle (800-1200 rpm) Needle drops sharply on a regular rhythm Burnt valve, or a valve with clearance too tight
Idle (800-1200 rpm) Needle drifts up & down, along with rpm drift Mixture off or small vacuum leak
Idle (800-1200rpm) Vacuum gradually drops Excessive exhaust back pressure (plugged muffler or catalytic converter)
Idle (800-1200rpm) Intermittent fluctuation Ignition miss; sticking valve
Idle (800-1200rpm) Steady, above 22 Ignition timing may be too advanced
Open & close throttle quickly Drops to about 2, jumps to about 25 Healthy engine
Open & close throttle quickly Drops to 0, jumps to about 20 May confirm worn rings (especially if idle shows only about 15-20) Verify with a compression or leakdown test.

George

 

Thanks for your reply George. Very detailed ! You say "A MAP sensor should read atmospheric at key on." Is it as easy as just turn the key to the on position and lookin at the reading of the scantool and comparing it to the barometer reading ? When you refer to key on lm asumming meaning not started just key on correct ?? I do have a vacuum gauge but its not a very expensive one.I just wondering if a cheap map sensor was something that would have been a problem to use ? When i read about map sensors the symptoms they talk about I have. Poor fuel mileage. Stuttering and misfiring. So when I replaced it I just bought a cheap sensor which got rid of the code that was coming up at the time. I'm not sure if I made a hugh mistake by buying cheap. I see the ac delco part is $75-150. I think I paid $20 for the one I bought. So I just thought before I fork out $85 bucks for an acdelco or Delphi part I would try to figure out if the $20 part is working correctly. Have you ever heard of people in the forum using these cheap sensors and having problems with them ? Would you recommend using a $20 one ?

 

Yes key on and the weather report.

Not sure on the Chineseum MAP sensor but in general non AC Delco electrical parts is a bad idea.

Your low idle vacuum may be the bigger story here and a comprehensive compression test and/or dynamic compression test may get to the bottom of your struggles by highlighting mechanical problems from a worn out engine.

George

 

Just want to talk a bit about use of Car Diagnostic Pro.

I have very little use for Gauges in Dashboard View. I noticed that you like to configure a ton of PIDs to make all the gauges that you may be interested in. However by doing this you are dramatically decreasing the number of scans/sec you get on each PID. With the BAFX you have a total of about 35 scans/sec to work with on a 2001 411 PCM (if that is what you have). Split this between 11 gauges and each gauge gives you an update only 3 times/sec. Now this might work fine for many PIDs that do not have rapidly changing values. But it does not work well for RPM, O2 sensors, fuel trims, etc - anything that changes rapidly.

Solution is to use Diagnostics to monitor only the specific PIDs of interest. If you're evaluating fuel trims or O2 sensors and the like, just look at what you need at the moment. You can easily and quickly generate a table with more than one PID or even add to the table. I am not aware of a way to save a table.

 

Ya I know you told me before I have too many PIDs running at once. That was and old screen shot. I only use one or two PIDs now at once.

 

I tested it today. Outside was 29.83 hg and the truck was 29.23 hg. Thanks for the information George it saved me from buying a new sensor 👍
I know i can test using a DMM and a vacuum gauge as well but i think that quick test was enough just to see its working.