: Strange sound and stalling of 99 sts



miwise
09-22-10, 12:17 AM
Ok. I bought another engine from a salvage yard. Didn't wanna do studs until I know the engine is good so I installed it in the car. Hooked up everything and having probs. The car is very hard to start. I have to hold the gas petal all the way Down to start it. Next it idles at around 3000 rpm at first crank then down to about 1500 or 2000 rpm. After idlingfor a few min it starts this sound from the intake like a rush of air sound or like a pressure cooker that the weight was removed from the lid. Shortly thereafter it will not crank. I will return the engine if no good but would like to know I didn't mess something up 1st I got all the intake bolts tight. As far as crank position sensors I plugged the grey into the top sensor and black into bottom. Hopefully I didn't reverse them. Please advise what I should check. The only code I get is a stall code

Ranger
09-22-10, 12:52 AM
Holding the pedal to the floor opens the throttle plate puts the PCM in "Clear Flood" mode and disables the injectors.

Listen closely to see if you can identify where that pressure cooker sound is coming from. That would be a big help.

miwise
09-22-10, 10:05 AM
It's coming right from the intake. The mass air flow intake

Submariner409
09-22-10, 11:00 AM
It's coming right from the intake. The mass air flow intake

Do you have the air cleaner ducting hooked up ?? A fast idling Northstar with attached MAF sounds like a big shop vac without the air intake "muffler' installed.

The engine should start immediately, idle at about 1200 for 15-20 seconds, drop to 900 for a minute or so, then to 650 - maybe something wrong with the Throttle Position Switch (Sensor) or the Idle Air Control solenoid (or you may have an Idle Speed Control motor).

miwise
09-22-10, 11:56 AM
Yeah. Same intake that was on the last motor. Same electronics. The only thing I'm unsure of is the crank position sensor. Idk if I plugged each one into the right place. Plugged grey 1 on the top sensor and black plug on lower sensor

Submariner409
09-22-10, 02:02 PM
Yeah. Same intake that was on the last motor. Same electronics. The only thing I'm unsure of is the crank position sensor. Idk if I plugged each one into the right place. Plugged grey 1 on the top sensor and black plug on lower sensor

Service manual wiring diagram.

miwise
09-23-10, 07:49 PM
Ok. I wound up replacing my intake b/c I found a crack in the old one. I had a few extras laying around. Anyways, got engine back together and it seems that I am still having problems. I figured it out tho. I'm pretty sure that the engine has at least one blown head gasket. The intake started to emit steam and drip water from it. I'm pretty sure that this is water. I'm on my second set of plugs now (tired of buying the same stuff twice) and that helped it a lot. Did compression test too and it seems that the rear bank is pretty low. 150 150 180 180 from 1 3 5 7 respectively. The front bank was mostly 185ish give or take about 5psi. I believe my compression tester reads a bit high too b/c this is the second engine to do this and read so high. I don't totally trust the measurements, but it does give a comparison b/w cylinders. I'm thinking that the head gasket has failed b/w cylinders 1 and 3. The pressure cooker sound seems to be gone though it is smoking a lot of white smoke.

Oh yes, one other thing. I called the people who sold me the engine. Good news, they offered to refund my money and resale the engine to me as a core. So I'll be studding the engine soon and putting a brand new set of upper gaskets on it. Hopefully will be able to put a set of MLS Cometic gaskets I hear so much about. I'm SOOOOOO tired of pulling this engine. This will be the third time. . .third time's a charm, right? I'm glad though I didn't redo the heads before testing the engine first. My main objective was to get an engine with a good lower end. I think I've accomplished that.

Ranger
09-23-10, 09:37 PM
A compression test will tell you nothing about the head gaskets. A leak down test will however.

miwise
09-23-10, 10:49 PM
I'll research how to perform leakdown test

tateos
09-24-10, 12:04 AM
Good luck Micah - keep the faith!

Richard Moore

Ranger
09-24-10, 02:12 AM
I'll research how to perform leakdown test

Check the Tech Tips forum.

miwise
09-24-10, 10:47 AM
Lol. I'm trying. This has been one disappointment after the next. I'm Just taking my time with it this time. I know I don't want to split open that lower unit though. I'll be buying all the stuff soon to do this job. Can't afford another screwup. I believe the this engine will perform great after this is done. What really sux tho is that it still needs other work done after this. Rear suspension work. Love the car but I regret starting this. If nothing though I'm persistent. I'm just ready to have a life outside of work again. Sometimes it seems I work work work just to come home and sink the money into a piece of crap that will get me nowhere. Hopefully that'll change tho soon and I'll be able to enjoy it.