TPI Tuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
Sponsored by:
Sponsored by:

Delphi MAF issue

Thread Tools
 
Search this Thread
 
Old 06-05-2023, 06:38 AM
  #1  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Delphi MAF issue

Figured I'd post the question before the story. Is anyone else having problems with Delphi MAF's? Any way to test them with a multimeter?
I recently installed a Delphi 10320 maf sensor to replace a stock bosch maf that gave constant code 36 burnoff issues. Now I have a rich condition (black smoke, eyes watering) and surging and dying at idle. The firebird had a rich issue before, but not nearly this bad. A little digging in this forum has shown other people having problems with the Dephi circuit board mafs. I am about to buy a reman Cardone 744712. Seems to be just like the stock Bosch with the wire.

The list of sensors I've already replaced are:
1:Coolant temp sensor to ecm
2. Tps
3. IAC (It was seized, probably should have changed this before the MAF)
4. ECM (crack in motherboard.)
Was not able to set IAC and TPS as per GM service manual instructions due to not being able to set idle low enough without dying.

Last edited by 89Formula2; 06-05-2023 at 06:44 AM.
Old 06-05-2023, 06:53 AM
  #2  
Supreme Member

iTrader: (8)
 
TTOP350's Avatar
 
Join Date: Oct 2001
Location: Il
Posts: 11,706
Received 754 Likes on 511 Posts
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Delphi MAF issue

Have you checked the fuel psi regulator vacuum line for raw fuel ?
Old 06-05-2023, 07:01 AM
  #3  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Fuel pressure regulator seems new, but have not checked vacuum line yet.
Old 06-05-2023, 08:34 AM
  #4  
Supreme Member

 
Edwardgp's Avatar
 
Join Date: Jan 2012
Location: Washington State
Posts: 1,987
Received 26 Likes on 24 Posts
Car: 1983 BB 1995 Z28 Camaro's
Engine: 454-350
Transmission: TH350-4l60e
Axle/Gears: 373 posi-Stock
Re: Delphi MAF issue

Well check out the vac line and let us know what you find. Good luck
Old 06-05-2023, 09:38 AM
  #5  
Supreme Member

 
SbFormula's Avatar
 
Join Date: Jun 2012
Location: Canada
Posts: 1,226
Received 149 Likes on 122 Posts
Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Delphi MAF issue

Delphi MAF issues
MAF issues
How to diagnose a MAF
Code 36
Code 34

https://www.thirdgen.org/forums/afte...or-review.html

https://www.thirdgen.org/forums/tech...t-ok-then.html

https://www.thirdgen.org/forums/tech...f-reading.html

Last edited by SbFormula; 06-05-2023 at 09:43 AM.
The following users liked this post:
Vader (06-09-2023)
Old 06-05-2023, 09:46 AM
  #6  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Thanks for the info guys. I'll check the vacuum line and maf readings after work. What are all of you using for a scanner? I have two obd2 scanners but they don't work for obd1.
Old 06-05-2023, 09:52 AM
  #7  
Supreme Member

 
SbFormula's Avatar
 
Join Date: Jun 2012
Location: Canada
Posts: 1,226
Received 149 Likes on 122 Posts
Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Delphi MAF issue

Originally Posted by 89Formula2
I recently installed a Delphi 10320 maf sensor to replace a stock bosch maf that gave constant code 36 burnoff issues. Now I have a rich condition (black smoke, eyes watering) and surging and dying at idle. The firebird had a rich issue before, but not nearly this bad.
Looks like the new Delphi MAF aggravated the problem. Not surprising. I would put the old MAF back on and ignore code 36 for now. The Delphi MAF, most likely, has the "voltage reading" issue described in the above posted threads.
For being too rich BEFORE: do you still have the original injectors?
Thanks
Old 06-05-2023, 09:52 AM
  #8  
Supreme Member

 
SbFormula's Avatar
 
Join Date: Jun 2012
Location: Canada
Posts: 1,226
Received 149 Likes on 122 Posts
Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Delphi MAF issue

Originally Posted by 89Formula2
Thanks for the info guys. I'll check the vacuum line and maf readings after work. What are all of you using for a scanner? I have two obd2 scanners but they don't work for obd1.
I used TunerPro with a ALDL cable.
Old 06-05-2023, 09:57 AM
  #9  
Supreme Member

 
SbFormula's Avatar
 
Join Date: Jun 2012
Location: Canada
Posts: 1,226
Received 149 Likes on 122 Posts
Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Delphi MAF issue

Originally Posted by 89Formula2
Thanks for the info guys. I'll check the vacuum line and maf readings after work. What are all of you using for a scanner? I have two obd2 scanners but they don't work for obd1.
I use TunerPro with a ALDL cable.
Old 06-05-2023, 10:12 AM
  #10  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Originally Posted by SbFormula
Looks like the new Delphi MAF aggravated the problem. Not surprising. I would put the old MAF back on and ignore code 36 for now. The Delphi MAF, most likely, has the "voltage reading" issue described in the above posted threads.
For being too rich BEFORE: do you still have the original injectors?
Thanks
Unfortunatly I do not have the original maf anymore, I cored it out. The PO installed new injectors right before I got the car. I can't see any part numbers on them, so I am very suspicious of them as well. I have Bosch 19lb gen 2 injectors from Southbay, and a Holley adjustable regulator waiting to be installed.
The following users liked this post:
SbFormula (06-05-2023)
Old 06-05-2023, 10:16 AM
  #11  
Supreme Member

 
SbFormula's Avatar
 
Join Date: Jun 2012
Location: Canada
Posts: 1,226
Received 149 Likes on 122 Posts
Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Delphi MAF issue

Originally Posted by 89Formula2
Unfortunatly I do not have the original maf anymore, I cored it out. The PO installed new injectors right before I got the car. I can't see any part numbers on them, so I am very suspicious of them as well. I have Bosch 19lb gen 2 injectors from Southbay, and a Holley adjustable regulator waiting to be installed.
Heck knows what the PO did eh? Could have a different tune in there too. It's going to be can of worms scenario. Don't give up.
Good luck
Old 06-05-2023, 12:12 PM
  #12  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

I solved the tune problem with ordering a stock tune on a replacement memcal from Tuned Performance. There was an old hypertech stage 1 chip on a moates piggyback for a 350. My firebird is a 305. The chip and the piggyback were all soldered together, that's why I just ended up getting a good used memcal.
The following users liked this post:
SbFormula (06-05-2023)
Old 06-05-2023, 04:01 PM
  #13  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Update: Found no fuel in the fuel regulator vacuum line.
Old 06-08-2023, 04:50 PM
  #14  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Update: Replaced Delphi MAF sensor with and reman Cardone 744712. I'm back to where I began. Slight rich condition, but not spewing out black smoke from the tailpipe. So the Delphi MAF was definitely defective. Tested fuel pressures. It was 36 at idle and 42 with just key on. Seems good if I'm not mistaken. I'm going to go ahead and swap in the Bosch injectors in a week or two.

Last edited by 89Formula2; 06-08-2023 at 07:12 PM.
The following users liked this post:
SbFormula (07-13-2023)
Old 06-13-2023, 09:12 PM
  #15  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Got antsy, replaced the injectors. Cleaned the intake plenum and runners at work. Installing the Holley fuel pressure regulator, egr valve, intake temp sensor, and reassembling everything by Saturday.





Old 07-12-2023, 03:37 PM
  #16  
Junior Member
Thread Starter
 
89Formula2's Avatar
 
Join Date: May 2023
Posts: 17
Likes: 0
Received 5 Likes on 5 Posts
Re: Delphi MAF issue

Problem solved. The injectors worked like a charm. I guess the previous owner installed the wrong injectors. No fumes from the exhaust, much better throttle response, and getting about 20-22 mpg cruising on the highway. Thank you everyone for the help.
The following users liked this post:
TTOP350 (07-12-2023)
Old 07-13-2023, 06:30 AM
  #17  
Supreme Member

 
SbFormula's Avatar
 
Join Date: Jun 2012
Location: Canada
Posts: 1,226
Received 149 Likes on 122 Posts
Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Delphi MAF issue

Originally Posted by 89Formula2
Problem solved. The injectors worked like a charm. I guess the previous owner installed the wrong injectors. No fumes from the exhaust, much better throttle response, and getting about 20-22 mpg cruising on the highway. Thank you everyone for the help.
Great!!!
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
kdxrider9262
TPI
3
04-24-2008 11:30 AM
TABBOO
TPI
15
08-22-2007 12:05 PM
vette&T/A
TPI
9
09-11-2005 11:16 AM
machinist
TPI
5
06-29-2003 02:45 PM



Quick Reply: Delphi MAF issue



All times are GMT -5. The time now is 12:23 AM.