light throttle hesistations with lean symptoms
#1
light throttle hesistations with lean symptoms
For the last few months my car has developed some hesitations during cruise situations. If I give it more than 1/3 throttle it generally smooths out but if I try to hold a steady rpm or try to accelerate slowly (to save gas) it keeps misfiring.
I recently installed an LC-1 with a G2 analog gauge and noticed that when the car is running fine my AFR's are around 14-15. As soon as the car starts to sputter the AFR's shoot all the way to 17-18 sometimes leaning all the way out on the gauge. Light throttle during highway cruises show 17-18 AFR's as well.
I did some research yesterday and saw that several people with similar problems had leaky injector grommets. I think that is a possibility with my secondaries because they didn't fit very snug initially but is there a way to check before I go pulling them out? I've heard of spraying carb cleaner and listening for idle changing but I would like to do some sort of pressure check and listen for leaks.
Any ideas guys?
Thanks,
~Ant
I recently installed an LC-1 with a G2 analog gauge and noticed that when the car is running fine my AFR's are around 14-15. As soon as the car starts to sputter the AFR's shoot all the way to 17-18 sometimes leaning all the way out on the gauge. Light throttle during highway cruises show 17-18 AFR's as well.
I did some research yesterday and saw that several people with similar problems had leaky injector grommets. I think that is a possibility with my secondaries because they didn't fit very snug initially but is there a way to check before I go pulling them out? I've heard of spraying carb cleaner and listening for idle changing but I would like to do some sort of pressure check and listen for leaks.
Any ideas guys?
Thanks,
~Ant
#3
TPS, was adjusted dead on back in december (still a possibility though), and 02 sensor has roughly 1,500 miles on it so its in good shape. Can the tps alone cause the car to cut fuel like that?
Thanks for the input arghx, you always give quick and helpful advice
Thanks for the input arghx, you always give quick and helpful advice
#5
Another thing I noticed today is the car goes very lean when even I boost slightly...almost like my secondaries aren't opening up or the computer isn't compensating for it. I'm running water injection set to come on at 1 psi right now to compensate for the high AFR's but I'd like to get to the bottum of this quickly so I can enjoy some real boost lol.
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#9
Discovered something today...the problem doesn't exist for a few minutes while the car is cold. I did a light pull while the car was cold and when the secondaries came in the AFR's went rich. Several minutes later the hesitations kicked in and AFR's went back to the 18's and the car would hardly accelerate...any more ideas on what could cause that symptom?
#13
High Comp Booster
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check that the range on the Tps is good No shorts or such, then look for leaks i used to do hvac and i could buy a "smoke bomb" that would burn for 1,2 or 5 mins to find leaks id say get a can and light it in the can and place where the filter is to find any leaks
the smoke should be harmless to the engine
or use brake cleaner when the car is warmed up to find a spot
check all the rubber on the engine something could be split after the maf
the smoke should be harmless to the engine
or use brake cleaner when the car is warmed up to find a spot
check all the rubber on the engine something could be split after the maf
#15
rotors excite me
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I've found sprays to be pretty useless. Get one of these:
http://www.boostpro.net/prodtester.html
But I've sealed up my intake pretty well with one of those and I still have this issue.
http://www.boostpro.net/prodtester.html
But I've sealed up my intake pretty well with one of those and I still have this issue.
#17
Eats, Sleeps, Dreams Rotary
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Is your pressure sensor still connected? Didn't you have that hose come off once before and cause a similar lean issue? Can't remember it's been a while since then.
#18
High Comp Booster
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if you go to an hvac store and ask for one they shouldn't be expensive at all it'll show any pin hole leaks no problem its not a common thing for cars but ive found it very handy
#24
rotorhead
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I think the plunger design is inherently prone to wearing out/failing. It's basically late 70s technology and all the OEM's moved away from it in the 90s. They use the rotating "slider" type potentiometers. FD and all the 90s Hondas have that design for the TPS, they're much more reliable.
#25
rotorhead
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ok so here's your plunger style TPS which began in series 3 Rx-7 (GSL-SE). The Bosch L Jetronic systems at the time had a closed throttle switch and a WOT switch and used the rate of change of AFM voltage for throttle pump function.
Now here's your basic slider-type TPS, this is the Denso/Toyota design:
now here is the FD TPS design:
and this is the NSX TPS:
I think you should check the voltage sweep of your TPS with an analog (NOT digital) voltmeter to see if there are any open circuits.
Now here's your basic slider-type TPS, this is the Denso/Toyota design:
now here is the FD TPS design:
and this is the NSX TPS:
I think you should check the voltage sweep of your TPS with an analog (NOT digital) voltmeter to see if there are any open circuits.