EFI mass air question
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From: maui.HI
EFI mass air question
I've recently swapped over to EFI (MAP). I'm thinking of converting over to mass air because of its ability to adjust and the many aftermarket performance products available for MAF. I've got several questions. I'm wondering if the A9 ECM is the best choice to search for? Do you select a manual trans type for a non-electronic overdrive trans like a C4? And would the A9 also adjust to a future stroker or a 351w swap? Thanks for any replies.
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From: Southern Oregon USA
The A9L is for a manual transmission and the A9P is for an automatic.
Either computer will work fine for a non electronic automatic application. There may be some minor changes needed in the NDS circuit for the manual computer. I have heard that the A9P has a little bit more aggressive spark timing and fuel management, but I've never confirmed it.
A stock ECM adapts pretty well to an increase in cubic inches. I know of at least one 427 stroker that ran really decent with a stock manual ECM (with some system mods). But to gain the most performance and best driveability, I would recommend an EEC Tuner or the TwEECer system.
Jason
Either computer will work fine for a non electronic automatic application. There may be some minor changes needed in the NDS circuit for the manual computer. I have heard that the A9P has a little bit more aggressive spark timing and fuel management, but I've never confirmed it.
A stock ECM adapts pretty well to an increase in cubic inches. I know of at least one 427 stroker that ran really decent with a stock manual ECM (with some system mods). But to gain the most performance and best driveability, I would recommend an EEC Tuner or the TwEECer system.
Jason
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From: maui.HI
Rcrawler, I installed the 19# inj yesterday. I started the engine and it wouldn't idle. I rechecked my vac. lines and reset base timing and idle/tps voltage as recommended. Still ran rough with wandering idle and black smoke coming from the tail pipe. Eventually it would stall and die. I couldn't keep the idle less than 1500 rpm. I assumed the ECM would relearn to the 19s but it didn't.
I just so happen had a ECM from a 88 mk7 HO. which I took a chance and connected. And holy moly, the idle started to settle. After driving it around , I could re-adjust the idle back to 750 rpm. And that slight hesitation was gone! Even the throttle response is much better (neck snapping)!
I just wanted to take this time to thank you and others, again for steering me through this swap. I think the next time I'll do 2 things differently. One is to look for a mass-air system because it is more adaptive, and secondly to obtain a complete EFI system from one known good running vehicle so all parts will be compatible. I'm quite please with my speed-density system for now as many others have had qreat results with their system. But I will try to buy more wisely the next time.
I just so happen had a ECM from a 88 mk7 HO. which I took a chance and connected. And holy moly, the idle started to settle. After driving it around , I could re-adjust the idle back to 750 rpm. And that slight hesitation was gone! Even the throttle response is much better (neck snapping)!
I just wanted to take this time to thank you and others, again for steering me through this swap. I think the next time I'll do 2 things differently. One is to look for a mass-air system because it is more adaptive, and secondly to obtain a complete EFI system from one known good running vehicle so all parts will be compatible. I'm quite please with my speed-density system for now as many others have had qreat results with their system. But I will try to buy more wisely the next time.
