Club G40 Forum
Technical => Engine and Transmission => Topic started by: grungeisdead on September 05, 2012, 12:49:24 am
-
Helloooo!
For those who don't know, I have a Mk1 Golf with a G40 Engine fitted, it also has a T25 Garret with a GT cam and the 6 psi boost switch mod.
The engine has ran sweet as a nut since I finished building it in November last year, my only gripe was max boost was 0.5 psi but I was never too fussed about it until I had replaced my fuel pumps.
I did some welding on the car a couple of months back, and had disconnected the battery while doing so, to avoid shorting any of the electrics, however ever since then I have been having running issues.
Basically, you would be driving along and start accelerating, the car would bog down like hitting a brick wall, with any amount of throttle pressure and this is only rectified by lifting my foot entirely off the throttle and then back on and it would go like shit off a shovel.
It's beginning to get more and more frustrating in daily driving and is taking its toll on already tired engine mounts with the constant accelerate, lift off, accelerate.
In my quest to solve it, ive done the following
New Inline Fuel Pump
New In Tank Fuel Pump
New Fuel Pump Relay
Cleaned Spark Plugs and set gap to 0.7mm (Tried both W5DP0's and NGK BP7EVX)
New Rotor Arm
New Dizzy Cap
New Spark Leads
Known working coil
New Coil
New Blue Temp Sender
Known working lambda
New Lambda
Replaced all engine earths and cleaned mounting points
Replaced all vacuum hoses
Of which have the following setup
2 brake servo take offs, one directly to FPR, one directly to ECU - ECU one is 470mm
Bottom of inlet manifold take-off has the following connected - dump valve, actuator, 6 psi boost switch and boost guage
Set the static timing using a screwdriver to note TDC and marked up the crank pulley and casing
Set timing to 6 deg at 2k rpm in service mode (was set to 10 deg)
Set CO to 0.7% in service mode using a gas analyser
Changed the actuator - which has finally given me a bar of boost (gave me 2 bar with a bleed valve - standalone from the rest of the vac system, plumbed into the main system now to avoid dangerous boost spikes)
Upgraded the coil to a 8v digifant GTI coil and amp
The CO will now only go down to 4.3% in service mode for some reason, and no amount of tweaking the CO changes it, this happened to my last CO pot, so replaced for another and its done it again)
The engine is running very rich, pretty much shows rich on the narrowband AFM all the time, apart when its bogging down, where when warm it reads in the middle)
Today when I was performing the 8v coil mod, I decided to check the ECU pinout to trace the black/green wire and noticed that inside the ecu connector plug was a load of water and some green furry connections! Its a wonder the car ever ran at all, So i stripped the ECU down, no water inside thankfully, and cleaned up all the connections and put it back together.
Driven home tonight and still got the same behaviour - driving along, car starts bogging down under any acceleration, lift off the throttle and back on it again and the car is happy again. also possibly worth noting that if you try and drive off with very light throttle the engine will try and cut out, so a bit more throttle and its sweet. It also backfires and pops on overrun. starts up and idles fine until warm where it occasioanly wants to drop the idle and sometimes cut out.
At the end of my wits now and have considered swapping it all out for my mapped G-lader setup, but it involves making a custom drivers mount, which I plain cant be arsed as I dont have a spare engine, so it would be an all or nothing affair.
Has anyone else experienced issues like this?
Things I have left to consider
Fit my wideband lambda - VEMS with datalogging - got my boss just need to fit an appropriate holesaw to drill out a hole in the exhaust, or take it to an exhaust place to do on the ramp
Check resistance and connectivity between the ecu pins and relevant sensors/ground
Check Pressure Switch calibration and wiring
Replacement MAP sensor
Replacement ECU
Put the G-lader stuff on
Help mehhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!
-
i'm having the same problem on a stock g40, i allready replaced the same as you did.
i'm starting to lose my mind arround this problem.. on mine, when i lift the throttle and put it down, it goes ok for 1 or 2 miles, then, it starts to bog again..
let me know if you find something!!
cheers
-
Check the harness connections and try a different ECU.
-
I've got a couple of ECU's (std and one with an SNS5 in) if you need to borrow one to check gimme a PM.
-
Cheers dude, I have a spare ECU in the post (forgot to pick it up when i picked up a spare engine) and a spare loom at the unit. I also have another ECU but its fitted with a 250kpa map sensor so no use without an appropriate map.
If I need it i'll give you a shout! need to catch up with your bro anyway been too long!
-
Connected up my wideband last night.
get around
10.1 -> 11 on start-up
14.7 -> 15.0 on partial throttle (about -0.3 bar on guage)
12 on boost
11.3 on full boost
19.5 on over-run/no throttle in gear
when it does start missing/bogging down the AFR values spiral upwards into mega lean.
Does this sound correct? CO Pot used at idle, lambda used at partial throttle, MAP used when WOT switch (in my case 6 psi switch is activated)
-
Too rich on boost, and that's fairly rich on cold start too.
It sounds like you'v never had the engine running full boost on this setup?
What's the map from?
-
Since last week is the first time I've ever had the engine pushing out over 0.5 bar boost, by changing the actuator. It's a new standard one, but as I now know the original actuator was at fault, I can splash out on a forge one now, happy in the knowledge.
the map history is unknown, it has turbo written on the chip, but the previous owner has very little history on the engine, unsure if he bought the chip seperately, or bought it as part of an engine conversion for his Mk2 olop.
I do want to get the car mapped, however I'm unsure if everything is healthy enough on the car, for the mapping session to be worthwhile. If I do get it mapped, i'll stick the 250kpa MAP sensor on along with some G60 injectors.
What is the potential problems that may be encounted by running the ECU with the 250kpa MAP sensor temporarily. will it just simply run like poo in comparion. I dont know enough about the sensors to even hazard a guess.
Can the map sensor be tested with a multimeter and some way of regulating pressure to the system with say a foot pump connected to the ecu vac take off?
-
250kPa sensor on a 200kPa map won't run.
I'd start with a known good map (that's actually for the spec you're running) and you know is for the 6psi boost switch.
You're pissing in the wind with some random chip.
-
hall sender issue?
-
Bumping an old thread here buts its a similar situation with my ppp map being very rich (only bogs on part throttle)
Cold start afr 10.3
Warm idle 15
Boost. 10-11
15% throttle 10-11
20-30% throttle 13-15
Over run 17- off the scale
Map is for my exact set up 1341 15psi, with 6psi switch. Got brand new bosh lambda and working blue temp
-
I never sorted this, started driving it again last month, spent a day troubleshooting but still couldnt get to the root cause, so ripped the engine out and stuck a G setup on it, whilst I muster up enough energy to look at this another time!
-
Bumping an old thread here buts its a similar situation with my ppp map being very rich (only bogs on part throttle)
Cold start afr 10.3
Warm idle 15
Boost. 10-11
15% throttle 10-11
20-30% throttle 13-15
Over run 17- off the scale
Map is for my exact set up 1341 15psi, with 6psi switch. Got brand new bosh lambda and working blue temp
Very light throttle application is too rich, other AFRs are okay for a generic chip. Is it light throttle no boost, or light throttle on boost that's doing it?
-
I think its the boost Andy, switch is defo at 6psi too. Won't be long till I'm changing the chip to the red injector one , still need to Pm you about it Andy. ALthough I don't wan't to push you whilst the baby is due!
-
If it's doing it on boost, it might be because you're running it at a lower boost level than the chip was mapped for. It's not dangerous, but obviously impacts driveability.
The chip's done for 15psi, which means that some map points are only passed-through briefly on a transient event, but end up having lots of fuel in to ensure the full boost/throttle fuelling remains spot on during spool-up. Now if you're running say 8psi, then the 'pass-through' map point might be used more frequently and for longer - and as you're on a lower boost it'll need less fuel.
I'd try and drive around it if you can for now, and then once the motor has a few more miles on it I'd wind the boost up and hopefully you'll find all is well.
Won't be doing any mapping for the next month or two, currently uber-busy getting ready for baby and trying to get my own Polo sorted in time. Once we've got sorted after the new arrival pops out; I'll try and post up a few mapping dates for people.
-
It might be different if tom has 8- 1 pistons if map is for 9s
-
Hmm yeah possibly Pete , I have the 8:1 pistons with the metal HG .
Andy yeah that sounds good mate, makes sense with the max boost pressure as I've got it at about 0.5 Bar to run it in. 300 more miles and I shall crank it up to a bar and we can talk about getting a chip sorted then a mapping day.
Cheers Lads
-
It might be different if tom has 8- 1 pistons if map is for 9s
Thanks for the advice Pete, but Tom's variant of G40008 is for 8:1 CR - have a few 'favours' of each map so can tailor them to spec. ;)
Edited to add - the transition to boost on all the turbo'd G40s can vary a bit depending on cam timing, actuator spring etc. etc. When doing a custom map it means that the light throttle/low boost area of the map often ends up having a lot of tweaking to the spec to fully optimise.
-
knew you'd be on the ball andy - just a suggestion! wasn't sure how many wossners youd mapped
-
Got my MOT done yesterday , failed on a couple of things including emissions ,
(http://i137.photobucket.com/albums/q236/etches69/null_zps7848eec9.jpg) (http://s137.photobucket.com/user/etches69/media/null_zps7848eec9.jpg.html)
AFR showing 15 on idle , didnt think it would be that rich
-
I think there might be a problem with your lambda. You say your gauge is reporting ~15:1 AFR at idle, and 14.7:1 is the ideal - anything swinging between 14.5:1 and 15:1 or thereabouts is normal.
However, the MOT man's probe is stating lambda 0.778 at idle - which is about 11.4:1 AFR! They don't match...
-
Yeah, ill need to adjust it on there gas analyser . Weird thing is Co pot adjustments arnt changing the mixture , I'm getting a reading across pins 1-3 so surely the variable resistor is working . Room temp sensor pins 2-3 show 2.3k ohms
-
I think there's a fundamental setup or lambda probe issue here.
Your wideband lambda is reading differently to the MOT centre's gas analyser.
-
Ok Andy, I shall just set the CO pot to a known decent value and get the wideband adjusted (if it can be) to their readings.
-
Are you still using the standard narrowband lambda?
-
Ok Andy, I shall just set the CO pot to a known decent value and get the wideband adjusted (if it can be) to their readings.
You have two faults to fix, possibly related - but maybe not:
1. Establish why the car is idling so rich. (Are you using the stock narrowband lambda still?)
2. Re-calibrate your wideband.
CO pot is for fine tweaking, not massive adjustment so it won't help you much here. I think you have a fundamental setup issue.
Are you still using the standard narrowband lambda? Is it known good and working?
Is the blue temp sender okay?
Which 250cc injectors are you using? Genuine G60 ones, or are they Ford 'motorsport' ones?
-
Brand new bosh lambda , known working blue temp sender , cleaned g60 injectors.
-
I'd run through the diagnostic guide on here checking everything back to the ECU connector pins.
11.4:1 AFR on idle is cold-start levels of richness. Do the engine revs rise when you unplug the blue temp sender?
Is the lambda probe earth connected?
Is the closed-throttle switch working?
What's the blue temp sender resistance measured at the ECU pins?
-
Yeah revs do rise when its unplugged, the lambda has been earthed . I'll have to have a look when I pick the car up from the test station tomorrow regarding the other stuff. Cheers Andy
-
Other possibility is that the MOT man didn't wait until it was warm... They should wait until the fan cuts in and then test after the fan has gone off.
-
Yeah they have dude, even tried raising the revs a little to see if the economy gets better but it gets even richer. Sounds to me similar to what Cheys had with his AAV. For the fuelling to be this far out its got to be either knackered lamda or something. Even though its been on for 800miles.
-
What's the part number on the injectors?
-
Part no for the injectors is : 280150905 (longest number on side) Which matches G60 greens .
Checked the blue temp 178 at about 90 deg on clock , 2.26k at 20 deg. Seems ok . Unplugged the lambda and the AFR showed an decrease in value and increased the smell of petrol.
-
It's difficult to say without seeing the car, but I don't think it's the same issue as Chris had if you've got genuine G60 injectors.
Run through the diagnostic guide on here, make sure you check sensor and switch resistances at the ECU connector as that way you're checking the wiring harness at the same time.
Did you check the idle switch was working?
What value is the CO pot set to?
What's your fuel rail pressure at idle with respect to atmosphere?
Did you manage to get your wideband re-calibrated correctly?
-
Yeah I shall do Andy, forgot to look at the idle switch as I only had a few mins shall check that this eve. CO pot I set to 700. Will have to borrow / buy a pressure tester for the fuel dude , my mate has gone on holiday so wont be able to use his works gas analyser for a few weeks. Just out of interest how did you convert % CO into AFR did you use an incomplete combustion equation or a value?
-
Did a little test today, measured the resistance of the blue temp circuit from the blue plug end. Measure 8.03k for mine and 6.23k for the mrs 1.3 polo. What sort of values have people got for this?
Cheers
Etches