Something went wrong last night-my Datsun is not happy

[karism]

So I was driving home last night from work , and something went wrong.

I was going around a bend doing 45mph in 3rd gear, boost gauge was reading 3PSI .The engine lost power all of a sudden. It didn’t die, and was still running, although it wouldn’t boost.I didnt drive it hard at all on my trip home

I looked at the gauges, and noted the following: Water temp was in the middle (normal temps) ,I had ¼ tank of gas, no warning lights were on. Ambient temp was about 65deg F.I stopped and opened the bonnet. All of the boost pipes were nice and secure. The CAS wiring was plugged in securely, as were all of the other sensors. I couldn’t check the fuel injector plugs, as I would burnt my hands to crap.BMC cone filter intact, and sealing properly. No oil/water in the engine bay. Engine bay was also normal temps ,and didn’t smell funny

I started the engine, and it idled like normal, no funny sounds, or smoke from the exhaust.

I was drivable in vacuum. As soon as it would edge towards ‘0’ on the gauge it would start spluttering. The turbo just wont start boosting. I didn’t attempt to keep my foot flat and see what happens, but i`am pretty sure it wont boost even at WOT

The engine has about 3000 on since being overhauled.

Specs as follows :Ca18DET. 10:1 Compression ratio , Stock T25 turbo, and intercooler. Boosting 10PSI (normally) Custom exhaust, BMC cone filter.BCPR7ES plugs,1600 miles on them. Oil is clean, and not mucky

Any ideas to what I can look for ?

karis

[themadscientist]

vacuum reading is as it was before?

Pull your plugs and see what they look like.

Do you have the ability to monitor fuel pressure?

My cold guess is pump is dead and as the boost comes on rail pressure collapses.

[MeanGreenS13]

+1

[bentvalves]

10:1 comp pistons - hells yea.

thing must feel great before boost comes on yea?

[ca18detgabby]

I would check and make sure the W/G is nice and secure.

[r34 gtr]

10:1 compression is gangsta as sh*t.

[Ca_Silvia]

That sounds like a boost leak for sure, same symtoms as me when i blew an intercooler pipe off.

[r34 gtr]

Having the MAF before the turbo is hilarious. I blew off an intercooler pipe the other day, but just kept driving because my car uses a MAP setup.

[themadscientist]

I was blowing through my AFM once and in the middle of a run I heard a "pop" and the car fell flat on it's face. I though I had done some kind of damage but it idled fine, revved no problem I got out and popped the hood. The incoming pipe blew off the AFM and it was just dangling there. I had gone from turbo to NA at 100MPH

[ca18detgabby]

I was blowing through my AFM once and in the middle of a run I heard a "pop" and the car fell flat on it's face. I though I had done some kind of damage but it idled fine, revved no problem I got out and popped the hood. The incoming pipe blew off the AFM and it was just dangling there. I had gone from turbo to NA at 100MPH

isnt the turbo creating suction toward the turbo? how would it pop off? or was it off throttle shuttering issues?

[float_6969]

It sounds like an ignition problem to me. Check your ignitor.

[karism]

Vacuum reading is exactlly like before. Pulling 14.7 " mercury at 800 rpm.

Well, my fuel pump is new (less than 2000 miles on) So it might be it!Havent checked it yet.

I`am going to pull the plugs tonight,and see what they look like.

[karism]

I would check and make sure the W/G is nice and secure.

Hmmm, i checked the wastegate.The actuator was secure to the gate.I will check it again.

[karism]

It sounds like an ignition problem to me. Check your ignitor.

Ok,thanks for the hint.Is there a special way i should test it?

Thanks for all the replies!Much appreciated!!!

[MeanGreenS13]

isnt the turbo creating suction toward the turbo? how would it pop off? or was it off throttle shuttering issues?

he had it setup blowthrough style. which means he had it on his charge pipe, most likely cold side.

[MeanGreenS13]

I would check and make sure the W/G is nice and secure.

if he had a wastegate issue, unless his flapper was wide open (which im sure you would notice by sound) it wouldnt just fall on its face like he is describing.

[r34 gtr]

Blow through MAF = Win. I really don't see why everyone doesn't run theirs that way.

[MeanGreenS13]

i would if i had the patience to get everything modified to work. I even thought about jus tputting the proper hole and inserting the sensor itself in my charge pipe and sealing it up nice, but i just dont have the time haha

[bentvalves]

why is blow through the win?

I could see oil being an issue in turbo cars hindering air flow readings

but I ask because now with my tubbed front fenders I dont have much room for the MAF anymore, I can squeeze it I think but I'll have to notch my fender a bit.

[boost_boy]

So I was driving home last night from work , and something went wrong.

I was going around a bend doing 45mph in 3rd gear, boost gauge was reading 3PSI .The engine lost power all of a sudden. It didn’t die, and was still running, although it wouldn’t boost.I didnt drive it hard at all on my trip home

I looked at the gauges, and noted the following: Water temp was in the middle (normal temps) ,I had ¼ tank of gas, no warning lights were on. Ambient temp was about 65deg F.I stopped and opened the bonnet. All of the boost pipes were nice and secure. The CAS wiring was plugged in securely, as were all of the other sensors. I couldn’t check the fuel injector plugs, as I would burnt my hands to crap.BMC cone filter intact, and sealing properly. No oil/water in the engine bay. Engine bay was also normal temps ,and didn’t smell funny

I started the engine, and it idled like normal, no funny sounds, or smoke from the exhaust.

I was drivable in vacuum. As soon as it would edge towards ‘0’ on the gauge it would start spluttering. The turbo just wont start boosting. I didn’t attempt to keep my foot flat and see what happens, but i`am pretty sure it wont boost even at WOT

The engine has about 3000 on since being overhauled.

Specs as follows :Ca18DET. 10:1 Compression ratio , Stock T25 turbo, and intercooler. Boosting 10PSI (normally) Custom exhaust, BMC cone filter.BCPR7ES plugs,1600 miles on them. Oil is clean, and not mucky

Any ideas to what I can look for ?

karis

Make sure the turbo is still spinning, too. Sounds like air to AFM issues or even the wiring to the AFM. Check the codes on your ecu since you've appeared to have done everything else.

Dee

[karism]

Good Morning Guys.

I took off all of the boost pipes again,en checked them.

Rechecked the ignitor.

Took of the Intake pipe,and had a decent look at the turbo.None of the blades are damaged,and it turns freely.No metal shavings or anything I allso saw that i`am not running the factory turbo anymore!I have a replacement T25,it has a different trim to normal,but iam not sure of the specs

I checked the injector plugs,they were all nice and secure.

I tried firing it up.Started instantly.

I let it warm up a bit,and drove it to the garage (filling station) filled some gas

I drove it back again. BY George! Its boosting!!!!smooth and happy like before.

So,its running fine again,but i have no idea what was wrong ??

Thanks for all the suggestions!

karis

[themadscientist]

Blow through MAF = Win. I really don't see why everyone doesn't run theirs that way.

I do it with the flapper door type but not the hot wire one. The flapper door can be adjusted with simple spring tension settings, is made of metal and does not have a fragile sensor doing the work in the hot oily air stream. The plastic hot wire AFM is fragile both in the the casing and in the sensor itself, bad juju.

[Liquid_Neon]

Good Morning Guys.

I took off all of the boost pipes again,en checked them.

Rechecked the ignitor.

Took of the Intake pipe,and had a decent look at the turbo.None of the blades are damaged,and it turns freely.No metal shavings or anything I allso saw that i`am not running the factory turbo anymore!I have a replacement T25,it has a different trim to normal,but iam not sure of the specs

I checked the injector plugs,they were all nice and secure.

I tried firing it up.Started instantly.

I let it warm up a bit,and drove it to the garage (filling station) filled some gas

I drove it back again. BY George! Its boosting!!!!smooth and happy like before.

So,its running fine again,but i have no idea what was wrong ??

Thanks for all the suggestions!

karis

prolly was a loose pipe somehwere, one that you couldnt see. happened to me for a week.. i thought my car was dying (which happened later anyway ) but it ended up being a charge pipe that was only half on, but it was still 'tight' feeling, so i didnt notice it being open on the other side.

[r34 gtr]

When I said blow through MAF for some reason I was picturing the 'ol 951, which does in fact have the barn door style MAF. I am dumb, should have realized that earler. I don't see why the hot wire MAF wouldn't work, but you would need some more than adequate intercooling before the MAF itself. Something like a Spearco liquid/air setup packed with dry ice.

[themadscientist]

Because it is made of thin plastic and has a very sensitive sensor that would right in the airflow. I'm sure everybody here has a littl oil in the intercooler, that crap would foul the wire too. The cleaning cycle they do when you turn on the ignition would not be able to keep the thing clean and you would get bad data right before the casing blew apart.

[mbmbmb23]

So,its running fine again,but i have no idea what was wrong ??

karis

Could have went into limp mode for whatever reason?