Quest4life Posted April 24, 2013 Report Share Posted April 24, 2013 Hi, I hope someone has an idea on this. 88 conquest. When I take off my wideband reads 17 and the car will stall if you don't fanese it until you get under way. Once you get going it runs around 12 to 14. Under boost it runs at around 11-12. We did check the TPS and it appears to be good. I believe it has a Gen 2 with a K&N air filter. It does have a walbro fuel pump and runs fine once you get going. The problem is only when starting out. Hot or cold it doesn't matter. I am looking for some possible causes. Thanks for any help. Link to comment Share on other sites More sharing options...
scott87star Posted April 24, 2013 Report Share Posted April 24, 2013 By take off I assume you're pressing the throttle, extra fuel must be added or it will go lean and that is the job of the ECU with input from the TPS. Download the FSM from www.starquestgarage.com so you can trace the wiring, check that you're getting a nice signal from the tps to the ecu when you depress the throttle. Assuming the TPS is good is not going to cut it on a 25 year old car. And the other thing to be thinking about is at cruise you're in closed loop with the O2 sensor feedback, when accelerating the ecu has to revert to the 5X7 fuel lookup table for fuel vs. Hz MAF output. You think it has a gen 2 Maf? Make sure that is up to snuff. Garbage in = garbage out. Link to comment Share on other sites More sharing options...
patra_is_here Posted April 24, 2013 Report Share Posted April 24, 2013 also, and I offer this as personal experience, not scientific, is that I have had a DSM maf that would allow too much air through the by-pass part of the MAF, and then the metering section would under-read the air-flow. but throttle tip-in sounds like you should check the TPS first. you could theorhetically block off part of the bypass on the MAF and go for a quick drive down the block and back to see if the MAF was under reading the enrichment. just an idea. btw, if you arent familiar, the maf has two parts, the square part that metered air flows through, and the bypass part the is two round tubes about an inch in diameter each, just above the square area. also, a malfunctioning BOV or other vacuum leak can cause lean on throttle tip in if coming out of low-load cruise Link to comment Share on other sites More sharing options...
StarquestRescue Posted April 24, 2013 Report Share Posted April 24, 2013 Can you take a picture of the maf? Does it still have the honeycombs in it? The stock and 1g maf ate the only ones that can be run with out a tuning system. Link to comment Share on other sites More sharing options...
Shelby Posted April 25, 2013 Report Share Posted April 25, 2013 you need to understand,, the diff from 12:1 and 14:1 is like walking 100 ft and running 2 miles ,, the two readings are miles apart and while looking check the air boot Link to comment Share on other sites More sharing options...
Technology Posted April 25, 2013 Report Share Posted April 25, 2013 Shelby, that might be a bit of an overstatement because the car will drive fine under vacuum at 12:1 and at 14:1. Under boost, yeah, it would be bad to run that lean. Basically there needs to be more fuel at tip-in. I don't know if a MAF-T gen 2 can be tuned for that. But the first thing to do is put the stock mass air sensor back on and see if the problem goes away. Link to comment Share on other sites More sharing options...
Shelby Posted April 25, 2013 Report Share Posted April 25, 2013 Shelby, that might be a bit of an overstatement because the car will drive fine under vacuum at 12:1 and at 14:1. Under boost, yeah, it would be bad to run that lean. Basically there needs to be more fuel at tip-in. I don't know if a MAF-T gen 2 can be tuned for that. But the first thing to do is put the stock mass air sensor back on and see if the problem goes away. under vacuum yes but rarely will you see much of a vacuum signal under excelleration ,and the difference is at 12:1 raw fuel will be pumping out the exh under light engine loads .but the main thing I was trying to point out to the OP is theres a huge diff in 12:1 and 14:1 this is like guys saying they only boost 10 to 20 lbs nothing huge or oil pressure is like 10 30 lbs at idle,, 30 is good but 10 is real bad Link to comment Share on other sites More sharing options...
patra_is_here Posted April 25, 2013 Report Share Posted April 25, 2013 wait is he running a MAFT??? i thought gen 2 meant gen 2 eclipse. Link to comment Share on other sites More sharing options...
StarquestRescue Posted April 25, 2013 Report Share Posted April 25, 2013 That's why i asked for a picture or some kind of descrition. am not sure what he means by take off either Link to comment Share on other sites More sharing options...
Technology Posted April 26, 2013 Report Share Posted April 26, 2013 I've never heard of a 2G eclipse called a Gen 2 eclipse. It's always 2G, but the MAF-T Gen 2 is a real product. Link to comment Share on other sites More sharing options...
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