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ECU Fuel Cut Question(s)


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#1 SA22C

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Posted 22 February 2018 - 03:38 PM

Hi guys!

In my pursuit of reliable horsepower for the ol' Conquest I have been slowly and methodically replacing and fixing  the things that needed addressed. Aside from the non-run issues I had to tackle when I bought the car I have also added a few aftermarket parts. The inevitable "fuel cut" issue has now shown up. I have read info from here and from  (in my opinion) one of the most knowledgeable Starquesters out there, that there is in fact no "fuel cut".  Now I cant for the life of me find the discussion where this issue is addressed. (If someone knows what I am talking about Id appreciate the info or a link)

The short version is that  the ECU doesnt have "fuel cut" per-se but the fuel cut issues are actually caused by the MAS being beyond maxed out, and the ECU cant interpret those signals any more, leading to the bucking/jerking associated with fuel cut.  

Ive read that swapping to a 1G MAS will eliminate the problem and everyone knows about the 88-89 ECU upgrade to accomplish the same results. There is also the MAFT/GM MAS option.  With 1G Turbo DSM's becoming increasingly rare, the probability of me sourcing a junkyard MAS is proving to be difficult.  I can buy a new MAS for around $150.00 and the 88-89 ECU's pop up from time to time and bring $175.00-$325.00.
The MAFT/GM option works out to be somewhere in price between them all.

Long winded, I know, and I apologize.  So can someone with the experience with these 3 options point me in a direction to go for?  They basically address the issue in different ways but which one of the 3 would you guys recommend? 1G MAS upgrade, ECU upgrade or the MAFT/GM MAS?  I get the ability to adjust some of the parameters of fuel management with the MAFT/GM option so that is the way I am leaning right now.
Anything else I might look for? Any reason (other than tuning) I should go one direction or the other?  

Thanks guys!





#2 tux

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Posted 22 February 2018 - 04:14 PM

I don't believe there is fuel cut on the 88/89.  But for sure on the 86 and below there is a fuel cut.  I think the 87 also had fuel cut.

#3 SA22C

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Posted 22 February 2018 - 04:53 PM

View Posttux, on 22 February 2018 - 04:14 PM, said:

I don't believe there is fuel cut on the 88/89.  But for sure on the 86 and below there is a fuel cut.  I think the 87 also had fuel cut.
Thank you but as I stated earlier there really isnt a "fuel cut" function of the ECU's (87-89). Its a result of the ECU not being able to process the jumbled and wrong signal generated by the over-taxed MAS.

#4 TexasQuest

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Posted 22 February 2018 - 06:17 PM

I've had both the the 1g dsm  & a maf-t. Go with the GM maf and translator. Well worth it.
88 Fiji Blue -Tsi
Zoom clutch, Fidanza flywheel, Stedebani shifter, KSport coilovers, ST swaybars, abs delete, a/c delete, cruise delete, JVE, BSEK, TEP steel brake lines, LSP braided cooler lines, CX Racing radiator,  MK1 silicone hoses, MK1 pullies, *DM hard pipes & intercooler,14G turbo, ported exh. manifold, MAF Translator, 3.5" GM maf, Turbo XS RFL bov, *DM 3" exhaust, Cusco front strut bar, TEP rear strut bar, Enkei 92's, HKS turbo timer, AEM wideband, AEM boost gauge, AEM oil pressure gauge, Hallman boost controller
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View PostJohnnyWadd, on 04 March 2010 - 10:01 PM, said:

my shaft was big i dont know what your talking about.

#5 SA22C

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Posted 23 February 2018 - 10:32 AM

View PostTexasQuest, on 22 February 2018 - 06:17 PM, said:

I've had both the the 1g dsm  & a maf-t. Go with the GM maf and translator. Well worth it.

That really is the direction I am leaning. I've been chasing a damn idle issue too. Im hoping this setup will help with that problem also.  
Did you notice any difference in idle quality when you made the change to either setup?

#6 TexasQuest

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Posted 23 February 2018 - 06:57 PM

Yes I did. The entire drive ability is way better than with the stock or the 1g maf.
88 Fiji Blue -Tsi
Zoom clutch, Fidanza flywheel, Stedebani shifter, KSport coilovers, ST swaybars, abs delete, a/c delete, cruise delete, JVE, BSEK, TEP steel brake lines, LSP braided cooler lines, CX Racing radiator,  MK1 silicone hoses, MK1 pullies, *DM hard pipes & intercooler,14G turbo, ported exh. manifold, MAF Translator, 3.5" GM maf, Turbo XS RFL bov, *DM 3" exhaust, Cusco front strut bar, TEP rear strut bar, Enkei 92's, HKS turbo timer, AEM wideband, AEM boost gauge, AEM oil pressure gauge, Hallman boost controller
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View PostJohnnyWadd, on 04 March 2010 - 10:01 PM, said:

my shaft was big i dont know what your talking about.

#7 SA22C

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Posted 23 February 2018 - 07:04 PM

That's good to hear! I just sent payment to StarquestRescue for the Maft-T setup he has listed in his thread. Fingers crossed this fixes the issues!

Thanks for the input. I appreciate it.

#8 croquest87

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Posted 24 February 2018 - 09:15 AM

maft and 3" gm mass  will give you option to control you afr  make sure to have something that will display your afr  i like aem afr gage w 02  it has on option that you set to p4  and converts signal to low voltage that our ecu can understand     works pretty good although it can be inconsistent at times  and may need tuned here and there    also will alow you to run larger injectors and such .  As far as boost limit on ecu i pushed my car to 20psi and hit no cut on 88-89 ecu inside 87 case on  87 car  although i wouldnt do it  past 15 if I had stock engine w unknown internal components. These  things like to go boom if overboosted. lol

#9 TexasQuest

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Posted 24 February 2018 - 03:18 PM

Definately install a wideband air/fuel ratio gauge with the maf-t.
88 Fiji Blue -Tsi
Zoom clutch, Fidanza flywheel, Stedebani shifter, KSport coilovers, ST swaybars, abs delete, a/c delete, cruise delete, JVE, BSEK, TEP steel brake lines, LSP braided cooler lines, CX Racing radiator,  MK1 silicone hoses, MK1 pullies, *DM hard pipes & intercooler,14G turbo, ported exh. manifold, MAF Translator, 3.5" GM maf, Turbo XS RFL bov, *DM 3" exhaust, Cusco front strut bar, TEP rear strut bar, Enkei 92's, HKS turbo timer, AEM wideband, AEM boost gauge, AEM oil pressure gauge, Hallman boost controller
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View PostJohnnyWadd, on 04 March 2010 - 10:01 PM, said:

my shaft was big i dont know what your talking about.

#10 SA22C

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Posted 24 February 2018 - 03:53 PM

An afr kit is in transit. Haha

#11 SA22C

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Posted 02 March 2018 - 10:47 AM

I got the Maf-T and GM Mas installed.  I cant believe the difference this thing makes. On all the stock settings I was still experiencing the sputter at idle. I enriched the idle via the translator and it went away completely. I can honestly say that it idles better than any Starquest I have ever messed with personally.

Thanks for all the input guys. I appreciate it and am glad i went the direction I did!

#12 TexasQuest

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Posted 02 March 2018 - 06:13 PM

Awesome glad to hear! I was the same way when I installed my maft setup, couldn't believe the difference.
88 Fiji Blue -Tsi
Zoom clutch, Fidanza flywheel, Stedebani shifter, KSport coilovers, ST swaybars, abs delete, a/c delete, cruise delete, JVE, BSEK, TEP steel brake lines, LSP braided cooler lines, CX Racing radiator,  MK1 silicone hoses, MK1 pullies, *DM hard pipes & intercooler,14G turbo, ported exh. manifold, MAF Translator, 3.5" GM maf, Turbo XS RFL bov, *DM 3" exhaust, Cusco front strut bar, TEP rear strut bar, Enkei 92's, HKS turbo timer, AEM wideband, AEM boost gauge, AEM oil pressure gauge, Hallman boost controller
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View PostJohnnyWadd, on 04 March 2010 - 10:01 PM, said:

my shaft was big i dont know what your talking about.

#13 croquest87

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Posted 02 March 2018 - 07:16 PM

Yup good upgrade! Now you can do some larger injectors and turn up the boost some to!




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