B18c Limp mode no cel
Hey guys, iv read and resd and read but i cant seem to work this car out. I purchased an eg b18c here in the u.k its been parked for 5 years.
The car revs to 4500 rpm than bogs down. I tried to pull codes but the light just stays on on both a virgin p30 and a htune chipped p28 with b18c basemap. So i cant seem to pull any fault codes. I bridge the connection and the light stays on constant.. doesnt go off at all.
Originaly i thought the car had a fuel cut as it would rev to 4500rpm and than cut.. stutter.. than regain idle. I put a gauge to the fuel rail and found it was losing fuel pressure. I unblocked the lines with air and found a large paper pellet in the line. Bingo! I thought i solved it.. fired up the motor.. still cuts fuel.
I did some more forum reading and found it was in limp mode. I have since replaced the distributor for a known good one.. tested figures for the tps sensor and evan replaced the tps sensor as someone on a forum tested the sensor to be good with a multimeter, but once replaced it the car was fixed. I have tested the map sensor with vacuum and multimeter.. still no joy
I have checked the engines grounds
Cleaned the iacv
New rotor arm
New ht leads
Fuel pump
Checked all sensor connections
Cleaned vtec solenoid - the wiring for this has been tampered with its got a single power going into the loom and is grounded at the thermostat.
Iv checked all plugs for burned pins etc
The timing belt was done by the last owner who claims he checked the physical timing twice over (he too tried to fix this car before i bought it) but for my own peace of mind i will check the physical timing tomorow
But the issue remains.. im a bit lost for direction now so any help is greatly appreciated. The dash loom was recently changed to obd1 to match the engine loom. I have a p28 chipped socketed by htune with a b18c basemap on it.
Thanks for your time
The car revs to 4500 rpm than bogs down. I tried to pull codes but the light just stays on on both a virgin p30 and a htune chipped p28 with b18c basemap. So i cant seem to pull any fault codes. I bridge the connection and the light stays on constant.. doesnt go off at all.
Originaly i thought the car had a fuel cut as it would rev to 4500rpm and than cut.. stutter.. than regain idle. I put a gauge to the fuel rail and found it was losing fuel pressure. I unblocked the lines with air and found a large paper pellet in the line. Bingo! I thought i solved it.. fired up the motor.. still cuts fuel.
I did some more forum reading and found it was in limp mode. I have since replaced the distributor for a known good one.. tested figures for the tps sensor and evan replaced the tps sensor as someone on a forum tested the sensor to be good with a multimeter, but once replaced it the car was fixed. I have tested the map sensor with vacuum and multimeter.. still no joy
I have checked the engines grounds
Cleaned the iacv
New rotor arm
New ht leads
Fuel pump
Checked all sensor connections
Cleaned vtec solenoid - the wiring for this has been tampered with its got a single power going into the loom and is grounded at the thermostat.
Iv checked all plugs for burned pins etc
The timing belt was done by the last owner who claims he checked the physical timing twice over (he too tried to fix this car before i bought it) but for my own peace of mind i will check the physical timing tomorow
But the issue remains.. im a bit lost for direction now so any help is greatly appreciated. The dash loom was recently changed to obd1 to match the engine loom. I have a p28 chipped socketed by htune with a b18c basemap on it.
Thanks for your time
Hey dude appreciate the tip, iv searched 10 pages of search results but could not locate the guide you mention. If you have a spare moment could you please drop me a link? Thanks dude
Check the physical timing yourself. Likely it has never been right since the belt was put on. This is a major reason to not rev up fully yet not throw a code either. It is not complicated to do, you only need to remove the top plastic cover and line up the marks.
If the check engine light comes on while driving, there is a code set. Pull over and jump the test plug while still running without turning the key off. If the memory backup circuit is bad, it will forget codes when you turn the key off.
If the check engine light comes on while driving, there is a code set. Pull over and jump the test plug while still running without turning the key off. If the memory backup circuit is bad, it will forget codes when you turn the key off.
Bit of an update i ripped out the engine loom to do continuity tests.. all clear however i noticed the oil pressure sensor was not connected.. probably cos the oil pressure sensor has been blocked on the back of the block. Can anyone clarify the importance of this sensor. Can it put my ecu into limp mode or isit purely for an oil light. Iv ordered one regardless but just wanted some clarity. Thanks again
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Bit of an update i ripped out the engine loom to do continuity tests.. all clear however i noticed the oil pressure sensor was not connected.. probably cos the oil pressure sensor has been blocked on the back of the block. Can anyone clarify the importance of this sensor. Can it put my ecu into limp mode or isit purely for an oil light. Iv ordered one regardless but just wanted some clarity. Thanks again
Does the "oil" light come on when you turn the key on but don't start?
There's often another one-wire device on the back of the engine block-- the knock sensor, and it will cause codes and runnability problems.
There's often another one-wire device on the back of the engine block-- the knock sensor, and it will cause codes and runnability problems.
Good point mk... the "low oil pressure light switch" is a yellow/red stripe wire with a single barrel connector and, if it hasn't been damaged, a teardrop shaped (maybe more like a Hershey's Kiss shape) rubber weatherproof cover that would fit over the sensor body. The Knock sensor appears like the typical 2-wire round GREY or GREEN plug style (like those found on the IAT ('92-95), ECT, IACV, PSP and fan switch), only there is one wire missing. The wire color is red/blue stripe. IF this is the sensor that is unplugged or missing/broken... then yes, you NEED to fix this if the ECU is looking for it. However, OP previously mentioned that no CEL or MIL code exists, so it is unlikely that the Knock sensor is the problem. Maybe you have a programmable/chipped ECU that either doesn't have a Knock sensor circuit and/or the ECU is programmed to ignore it.
Good point mk... the "low oil pressure light switch" is a yellow/red stripe wire with a single barrel connector and, if it hasn't been damaged, a teardrop shaped (maybe more like a Hershey's Kiss shape) rubber weatherproof cover that would fit over the sensor body. The Knock sensor appears like the typical 2-wire round GREY or GREEN plug style (like those found on the IAT ('92-95), ECT, IACV, PSP and fan switch), only there is one wire missing. The wire color is red/blue stripe. IF this is the sensor that is unplugged or missing/broken... then yes, you NEED to fix this if the ECU is looking for it. However, OP previously mentioned that no CEL or MIL code exists, so it is unlikely that the Knock sensor is the problem. Maybe you have a programmable/chipped ECU that either doesn't have a Knock sensor circuit and/or the ECU is programmed to ignore it.
Obd1 dash loom
Obd2a engine loom
P28 chipped htune ecu
Do these 3 tend to work together plug and play?
Last edited by imran_akn; Jul 3, 2019 at 03:36 AM.
Hey buddy i have a new chipped p28 with a b18c jdm itr basemap.. the dash loom is obd1 the engine loom does not seem to have any plug for a knock sensor. And from my understanding the chipped p28 they disable the knock sensor when they programme it. (Please correct me if anyone knows better wiring and looms is not my strong point. Kind of picking up someone elses mess they couldnt get it working)
Obd1 dash loom
Obd2a engine loom
P28 chipped htune ecu
Do these 3 tend to work together plug and play?
Obd1 dash loom
Obd2a engine loom
P28 chipped htune ecu
Do these 3 tend to work together plug and play?
Thank you for the clarification. I removed the engine loom but found no obvious issues. I will be replacing the following on reassembly
Ignitor module
Lambda
Adding the oil temp sensor for the hell of it
If that doesnt work i will probably have to try another distributor. I have tested by multimeter and all sensors seem to be correct. I just cant get the car to rev over 4500 rpm. Some posts in other threads have ended up being sensors which tested out correctly but for unknown reasons didnt let that car out of limp mode.
Another guy said he had a issue with his distributor plug so i will check each pin for continuity. If not i can only think of ckps sensor inside it.
Thanks again all. Appreciate any help
Ignitor module
Lambda
Adding the oil temp sensor for the hell of it
If that doesnt work i will probably have to try another distributor. I have tested by multimeter and all sensors seem to be correct. I just cant get the car to rev over 4500 rpm. Some posts in other threads have ended up being sensors which tested out correctly but for unknown reasons didnt let that car out of limp mode.
Another guy said he had a issue with his distributor plug so i will check each pin for continuity. If not i can only think of ckps sensor inside it.
Thanks again all. Appreciate any help
Right so new distributor is in.. the car runs well but the 4500 limp mode fuel cut still occurs
Checked the physical timing. As pictured
Checked loom for continuity
Cleared fuel lines
Changed fuel pump
Checked grounds
Changed ecu
Changed tps
Changed map
Changed ignitor
Changed distributor
Changed lambda
Htune P28 chipped with b18c map
From what i hear the dash and engine looms have been replaced too.
Im totally lost with this one lol the cars been off the road for about 5 years. Runs smooth just cuts are 4500rpm and bogs.
When i removed the valve cover i found a thin glaze of white mayo on the cam rails. Bearing in mind it hasnt been driven for 5 years do you think its anything to worry about?
Send Help please.
Last edited by imran_akn; Jul 17, 2019 at 07:44 AM.
Hey buddy as far as i can tell the only 2 connectors which can be mixxed are the tps and map.. but as iv read the map wires are longer?
Clogged cat.. im literaly out here with the car now.. removed the catback and revved.. still bounced at 4500rpm
Il get ther.. just out of ideas for today
Any helps greatly appreciated
Clogged cat.. im literaly out here with the car now.. removed the catback and revved.. still bounced at 4500rpm
Il get ther.. just out of ideas for today
Any helps greatly appreciated
Some of the 2P connectors can also be swapped. Check them all using the connector wire colors to be safe. It's an extremely common mistake when swapping engines.
Swapped sensor connectors may also fry the ECU.
Il double check again tomorow. But when i did continuity from the sensors to the ecu plug i labelled the loom up and all seemed to match up to the ecu pins. But il double check again tomorow with the hope i find something i may have missed.. if anyone can think of anything else please let me know as im out of ideas and dont really want to give up lol
Bit of help, can anyone point me in the direction of the obd2 distributor wiring diagram. Similar to as pictured but with all wires labelled
Last edited by imran_akn; Jul 20, 2019 at 09:39 AM.






