More starting problems, (fresh rebuild)
09-19-08, 05:12 PM
#1
More starting problems, (fresh rebuild)
1988 Turbo II, 0 miles on rebuild.
I have been starting it a couple times a day for the past 2-3 days. It starts a lot easier than it used to, only cranks for maybe 5 seconds before it blasts off now.
What happens is the tach climbs to 4k, and sits around there for maybe 10-15 seconds, and then the engine just dies, adding throttle does not help it at all.
What i have checked is:
-AFM resistances are all good.
-Checked my TPS, the resistance when closed is around 2.5k-3k, severely out of spec, and when WOT it is an even climb to 7k.
No emissions, no bac, no nothing. No vacuum leaks, checked with a vacuum cleaner hooked up to the throttle body elbow.
I have yet to check for voltage coming from the AFM sensor plug.
Any suggestions?
I have been starting it a couple times a day for the past 2-3 days. It starts a lot easier than it used to, only cranks for maybe 5 seconds before it blasts off now.
What happens is the tach climbs to 4k, and sits around there for maybe 10-15 seconds, and then the engine just dies, adding throttle does not help it at all.
What i have checked is:
-AFM resistances are all good.
-Checked my TPS, the resistance when closed is around 2.5k-3k, severely out of spec, and when WOT it is an even climb to 7k.
No emissions, no bac, no nothing. No vacuum leaks, checked with a vacuum cleaner hooked up to the throttle body elbow.
I have yet to check for voltage coming from the AFM sensor plug.
Any suggestions?
09-20-08, 06:58 AM
#3
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
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Large air leak from the turbo inlet duct. Maybe one of the holes on its aft side is open. Like where the bov and purge checkvalves go in it. Or the BAC on the stock engine has a air line to it from the turbo outlet duct that might be open. I know the BAC has been removed, but did you plug that air hole on the turbo outlet duct?
Or the brake booster line on the back of the trottle body is not connected up. But that should have been caught when looking for air leaks at the throttle body elbow.
I'd say the fuel is probably right if you jumper the fuel pump check connector and can hear the fuel running back into the tank constantly with the key to ON.
A huge leak at the grommet at the bottom of the fuel injectors is a thought. As in rock hard grommets leaking air.
If it's a series four, pull the TPS plug off and see if there is a difference. That should have no effect on starting at all. I'd look and see if the throttle plates are fully closed or not. You didn't mention if the water thermowax is still on the engine or not. If it's connected, then that'd explain why the TPS reads off and would explain the throttle plates being cracked open rather than fully closed.
You could leave the jumper in the fuel pump check connector all the time while your checking things out. That would keep the pump running even if there was a problem with the afm's fuel switch.
Just above the BAC there should have been a large nipple that connected the BAC with a solenoid bolted just to the right of the intercooler. Is that large nipple capped. And are the nipples on the right aft side of the intercooler capped off?
It still sounds like a large air leak. Most likely b/t the throttle body elbow and the turbo inlet duct. Just a guess. Nobody can say for sure when they aren't there.
Or the brake booster line on the back of the trottle body is not connected up. But that should have been caught when looking for air leaks at the throttle body elbow.
I'd say the fuel is probably right if you jumper the fuel pump check connector and can hear the fuel running back into the tank constantly with the key to ON.
A huge leak at the grommet at the bottom of the fuel injectors is a thought. As in rock hard grommets leaking air.
If it's a series four, pull the TPS plug off and see if there is a difference. That should have no effect on starting at all. I'd look and see if the throttle plates are fully closed or not. You didn't mention if the water thermowax is still on the engine or not. If it's connected, then that'd explain why the TPS reads off and would explain the throttle plates being cracked open rather than fully closed.
You could leave the jumper in the fuel pump check connector all the time while your checking things out. That would keep the pump running even if there was a problem with the afm's fuel switch.
Just above the BAC there should have been a large nipple that connected the BAC with a solenoid bolted just to the right of the intercooler. Is that large nipple capped. And are the nipples on the right aft side of the intercooler capped off?
It still sounds like a large air leak. Most likely b/t the throttle body elbow and the turbo inlet duct. Just a guess. Nobody can say for sure when they aren't there.
Last edited by HAILERS; 09-20-08 at 07:20 AM.
09-20-08, 09:24 AM
#4
First picture to my photobucket shows a pretty large crack on the airbox-turbo air duct.
Second picture shows my block off plates, which have no leaks. (I physically hooked a shop-vac up to the throttle body elbow coupler, and while it's running you can easily hear any leaks. I found one, patched it, and now i hear or feel nothing, even around the fuel injector area.)
Third picture, nothing special.
http://s143.photobucket.com/albums/r.../Engine%20bay/
Second picture shows my block off plates, which have no leaks. (I physically hooked a shop-vac up to the throttle body elbow coupler, and while it's running you can easily hear any leaks. I found one, patched it, and now i hear or feel nothing, even around the fuel injector area.)
Third picture, nothing special.
http://s143.photobucket.com/albums/r.../Engine%20bay/
09-20-08, 11:25 AM
#5
Some more new information. I have reason to believe my fuel system is working perfectly.
I grabbed my ohm reader, set it to DC, and started checking the pins of the AFM sensor plug (harness side). Just checking pins at random, and then i checked the first two pins, as i did that i heard fuel pump into the fuel rails. So it sounds like the priming system is working fine, and my fuel pump is good, otherwise i don't think it would do that.
This is leading me to believe there is something physically wrong with my AFM. The resistances check out fine though. Is there anyway to play around with the AFM to see if the car stays running?
I grabbed my ohm reader, set it to DC, and started checking the pins of the AFM sensor plug (harness side). Just checking pins at random, and then i checked the first two pins, as i did that i heard fuel pump into the fuel rails. So it sounds like the priming system is working fine, and my fuel pump is good, otherwise i don't think it would do that.
This is leading me to believe there is something physically wrong with my AFM. The resistances check out fine though. Is there anyway to play around with the AFM to see if the car stays running?
09-20-08, 12:26 PM
#6
***Update***
I temporarily fixed the crack in the turbo duct. When i now turn the car on, it starts right up, the tach climbs to about 2.5k and then the engine dies. If i stay on the throttle i can keep it going, but as soon as i let off it drops suddenly, and it is very hard to bring the engine back up with throttle.
When the engine was running with throttle it was very rough and i'm sure getting a new TPS would fix that.
So right now i have the throttle cable tightened as much as it can go, the plates are probably open 20-30 degrees, this is so it can maintain idle on it's own. Letting it unflood now, we'll see what happens shortly!
I temporarily fixed the crack in the turbo duct. When i now turn the car on, it starts right up, the tach climbs to about 2.5k and then the engine dies. If i stay on the throttle i can keep it going, but as soon as i let off it drops suddenly, and it is very hard to bring the engine back up with throttle.
When the engine was running with throttle it was very rough and i'm sure getting a new TPS would fix that.
So right now i have the throttle cable tightened as much as it can go, the plates are probably open 20-30 degrees, this is so it can maintain idle on it's own. Letting it unflood now, we'll see what happens shortly!
09-20-08, 11:30 PM
#7
http://s143.photobucket.com/albums/r...taillights.jpg
That is the middle bolt hole to the lower intake manifold. It is leaking coolant, not fun.
Anyone know the size of this said bolt, and if it's possible to get that bolt in there without taking the turbo+manifold off.
That is the middle bolt hole to the lower intake manifold. It is leaking coolant, not fun.
Anyone know the size of this said bolt, and if it's possible to get that bolt in there without taking the turbo+manifold off.
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09-22-08, 12:42 PM
#8
HAILERS
Join Date: May 2001
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If you jumper the yellow two socket fuel pump check connector, the fuel pump will run constantly even if the afm is in the backyard buried with your gold ingots.
I think your out of luck with the center bolt on the manifold. Guessing you'd have to remove the turbo.
Seems the brake booster line is on. Red outfit going to the firewall.
How are things if you get the engine up to temperatures. Any better/worse?
It might help if the key is put to ON and each pin on the ECU plugs is checked with a meter and compared to the inputs/outputs in the Fuel and Emissions section of the FSM.
Stock fuel pump? Stock would be best imho right now.
Maybe one of the three hose on the back of the throttle body is conneted wrong? Big nipple goes to the omp spider then to the oil injectors top nipple. Bottom nipple is the only on that has vacuum and goes to the water thermo valve just to the left of the nipple, OR plug that metal nipple. Either of the top nipples go to a vacuum hose going to the nipple b/t the two oil injectors on the intake manifold.
As far as tps go, I'd try it with it disconnected and see if there is an improvement or not. If the engine was HOT, I'd see how much voltge is on pin 2G of the ECU middle plug. A green/red wire. You'd have to have the plugs all connected and backprobe that wire with the meter. Maybe ***** that wire with a sewing needle and hold the meter lead to the sewing needle. ONE VOLT DC is desired. Approx one volt is fine. Like 0.95vdc or 1.05vdc are approx and fine as frogs hair. With a meter on that wire, key to ON, you could move the throttle thru its tavel and the voltage should go up as you depress the pedal to approx 4.5 vdc or so.
Somehow, make sure the LEAD plugs are firing. Could be it's running on TRAILS only. Easy to test. Just remove the Trail sparkplugs and start the car. If it starts the LEAD are working. Trails do very little imho at idle etc, but if the LEAD are not working and it's running on Trail, it won't run very well at all.....ever.
I think your out of luck with the center bolt on the manifold. Guessing you'd have to remove the turbo.
Seems the brake booster line is on. Red outfit going to the firewall.
How are things if you get the engine up to temperatures. Any better/worse?
It might help if the key is put to ON and each pin on the ECU plugs is checked with a meter and compared to the inputs/outputs in the Fuel and Emissions section of the FSM.
Stock fuel pump? Stock would be best imho right now.
Maybe one of the three hose on the back of the throttle body is conneted wrong? Big nipple goes to the omp spider then to the oil injectors top nipple. Bottom nipple is the only on that has vacuum and goes to the water thermo valve just to the left of the nipple, OR plug that metal nipple. Either of the top nipples go to a vacuum hose going to the nipple b/t the two oil injectors on the intake manifold.
As far as tps go, I'd try it with it disconnected and see if there is an improvement or not. If the engine was HOT, I'd see how much voltge is on pin 2G of the ECU middle plug. A green/red wire. You'd have to have the plugs all connected and backprobe that wire with the meter. Maybe ***** that wire with a sewing needle and hold the meter lead to the sewing needle. ONE VOLT DC is desired. Approx one volt is fine. Like 0.95vdc or 1.05vdc are approx and fine as frogs hair. With a meter on that wire, key to ON, you could move the throttle thru its tavel and the voltage should go up as you depress the pedal to approx 4.5 vdc or so.
Somehow, make sure the LEAD plugs are firing. Could be it's running on TRAILS only. Easy to test. Just remove the Trail sparkplugs and start the car. If it starts the LEAD are working. Trails do very little imho at idle etc, but if the LEAD are not working and it's running on Trail, it won't run very well at all.....ever.
Last edited by HAILERS; 09-22-08 at 01:01 PM.
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