LS Vtec Woes - TriStateTuners.com :: Home of Tristate Auto Enthusiast

96Clipse · 10-16-2011, 02:12 PM

So I have a serious stumper on my hands with my LsV swapped em1.
The car has been running on this swap great for over a year, but I went out to start it yesterday and it starts for 2 seconds then dies. It will constantly fire up but die right away, and if I hit the gas it dies even faster like its not getting enough gas. So I checked fuel pressure and its good, all injectors are getting powered, but I think they may not be getting pulsed after the engine starts.
I have spark, and my timing is known good because the car ran fine before.
Here's the kicker, when messing around with known honda problems, I thought hey maybe my map and iac are switched, so i switched them and it started up and would idle, but goes into limp mode and won't rev when you hit the pedal.
So I switched them back but left the map sensor unplugged, and surprisingly the car started right up and idled fine, i started it three times and every time it idled normal. So i tried revving it up, and it rev'd up fine, but when coming back to idle stalled out and wouldn't restart, just cranks continually, which im 99% sure is cuz the engine flooded with gas. So I have it sitting right now clearing out. I have searched all over the honda forums etc and found other people with exactly the same problem but none of the threads have any final conclusions in them. All of these other people have tried replacing map sensors, distributors, ecu's, plugs, wires, iac valves all multiple times with no success. Anyone with any other suggestions i'd really appreciate it, i'm stumped because it has enough fuel to start, but seems as if it isn't opening the injectors after the car starts, only when the map sensor is unplugged and the car is running on default mapping can it idle and rev.

Thanks for reading and any advice!

saxon · 10-16-2011, 05:40 PM

it sounds like your map sensor died on you, if you unplugged that and it started

DPancoast · 10-16-2011, 06:31 PM

Try a new map sensor. I have one from my 96 b18b1 if it is compatible that if you are local you can have or I'll send it to you for envelope costs lol.

Also clean and check your iacv to make sure it's good to go just in case.

96Clipse · 10-17-2011, 12:02 AM

Yea the map sensor did seem most logical to me seeing as plugged in it doesn't run, unplugged it does, I'm just unsure where to go from there if it doesn't work seeing as others have replaced their map sensor and the problem wasn't fixed.
But none the less I will try putting a map sensor on it, and a new iac seeing as I've known mine was bad for awhile, i just have it bypassed. Hoping those will fix it but as I have a bad feeling it won't i'll keep this updated.

LightningTeg · 10-19-2011, 02:33 AM

Map sensor

10-16-2011, 02:12 PM	#1
96Clipse Tri-State Aficionado Join Date: Jan 2010 Location: Springfield, PA Member #15606 My Ride: 2000 Civic Si iTrader: (0)	LS Vtec Woes So I have a serious stumper on my hands with my LsV swapped em1. The car has been running on this swap great for over a year, but I went out to start it yesterday and it starts for 2 seconds then dies. It will constantly fire up but die right away, and if I hit the gas it dies even faster like its not getting enough gas. So I checked fuel pressure and its good, all injectors are getting powered, but I think they may not be getting pulsed after the engine starts. I have spark, and my timing is known good because the car ran fine before. Here's the kicker, when messing around with known honda problems, I thought hey maybe my map and iac are switched, so i switched them and it started up and would idle, but goes into limp mode and won't rev when you hit the pedal. So I switched them back but left the map sensor unplugged, and surprisingly the car started right up and idled fine, i started it three times and every time it idled normal. So i tried revving it up, and it rev'd up fine, but when coming back to idle stalled out and wouldn't restart, just cranks continually, which im 99% sure is cuz the engine flooded with gas. So I have it sitting right now clearing out. I have searched all over the honda forums etc and found other people with exactly the same problem but none of the threads have any final conclusions in them. All of these other people have tried replacing map sensors, distributors, ecu's, plugs, wires, iac valves all multiple times with no success. Anyone with any other suggestions i'd really appreciate it, i'm stumped because it has enough fuel to start, but seems as if it isn't opening the injectors after the car starts, only when the map sensor is unplugged and the car is running on default mapping can it idle and rev. Thanks for reading and any advice!

10-19-2011, 02:33 AM	#5
LightningTeg Tri-State Aficionado Join Date: Feb 2011 Member #19731 My Ride: 513whp 98' Integra iTrader: (0)	Map sensor __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures. 97' Civic EX bone stock DD 98' Integra LS, 500whp +

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10-16-2011, 05:40 PM	#2
saxon Tri-State Addict Join Date: Sep 2011 Member #21656 My Ride: 2015 m3 iTrader: (1)	it sounds like your map sensor died on you, if you unplugged that and it started

10-17-2011, 12:02 AM	#4
96Clipse Tri-State Aficionado Join Date: Jan 2010 Location: Springfield, PA Member #15606 My Ride: 2000 Civic Si iTrader: (0)	Yea the map sensor did seem most logical to me seeing as plugged in it doesn't run, unplugged it does, I'm just unsure where to go from there if it doesn't work seeing as others have replaced their map sensor and the problem wasn't fixed. But none the less I will try putting a map sensor on it, and a new iac seeing as I've known mine was bad for awhile, i just have it bypassed. Hoping those will fix it but as I have a bad feeling it won't i'll keep this updated.