99 malibu died on hwy, have spark, fuel pump buzz, but no fuel pres @ rail!?

[manicmechanix]

Yeah I said 41 psi because I believe that was still the spec for '99. I agree it doesn't sound like you have a fuel supply problem. I wouldn't go changing the CKP sensors just yet, you should check it first anyway.

I'd check the ignition spark condition, coil resistance and wire resistance, spark plugs etc. I'm thinking you might have an injector problem. I would check their resistance at the 10 way connecter. They might be clogged, combined with bad gas and they aren't the most reliable injector models around.

[Scott-Ohio]

Thanks Airjer, I appreciate that immediate stall insight--makes good sense.

Since I had spark from that #4 plug wire earlier during this diagnosis, I was maybe too quick to think fuel, but thought low fuel pressure might cause same immediate stall. But now that I've got the correct 41-47 psi, I'm thinking I should check each coil like you suggest and ignition control module too.

Unfortunately, my 6-month old battery (good 8-year one too!) no longer has enough charge to turn engine over, so I am re-charging it. I think it's very odd that it is so weak since parking brake has been set (which keeps the headlights from automatically switching on) and I've only switched on ignition for the most part and during brief periods of running engine, alternator should've charged battery while running. I sure wouldn't think an alternator/built in voltage regulator suddenly failing would cause engine to suddenly stall, would it?!

Anyhow, I recall I had replaced the front 3 plugs when I first bought car (~100k miles) with good AC Declo 41-940's, and always intended to get back 3, but simply forgot and although I've never personally experienced a spark plug failure, I've heard it can happen, sooooo, I'll likely do this now too.

Both the 7X crankshaft position sensor and camshaft position sensor check out to be good, so I believe I'm down to ignition control module, coil packs, spark plugs and wires, and very long-shot the PCM. Again, I don't believe a suddenly failed alternator/voltage regulator would cause the engine to suddenly stall while cruising along at 70MPH on the hwy, but will test it now too since this weak battery also baffles me.

Thanks again and please don't hesitate to respond with any other thoughts, I really do appreciate it!

Take care, Scott

[Scott-Ohio]

Thanks manixmechanics, just noticed your post--didn't realize there was a 2nd page on this thread already.

I wasn't aware of a connector to check resistance on injectors--I thought I'd have to remove the upper plenum to get my test leads on them, thanks! Can you tell me where I might find that 10-way connector? I'd definitely like to read their resistance too.

I really do appreciate your thoughts inputs on this matter.

I'll keep all posted after I do more testing on this beast!

Thanks and take care, Scott

[manicmechanix]

Yeah the 10-way connector is by between the alternator and coil pack. Since you have SFI, the injectors have wiring for each at the connecter. They share a common power feed but since they have seperate grounds terminals at the connector, you can check each between the pink power and each of the black striped wire grounds. This won't tell you if the injectors are restrictive and clogged up though.

A bad alternator won't keep it from running but if battery voltage drops too low engine will shut down by the PCM.

[Scott-Ohio]

Wow, this has really gone from bad to worse! I went ahead and replaced all 6 spark plugs, tested plug wires, measured primary and secondary resistance on all 3 coil packs--all measured exact same as new Standard Ignition brand at store 1.2 Ohms (pri) and ~5.7K Ohms (sec), tested ignition control module (guy at Advance cycled test 3x to allow module to get good and hot) and it passed with flying colors. I also checked resistance of all 6 fuel injectors at the 10-pin connector (mentioned by manixmechanics--thanks) and they all measured ~13.5 Ohms each. So with well charged 1 year old battery (8-year 700 CCA) all I got was the solemn sound of a solenoid click!

So off to AutoZone to test the starter and battery. Didn't bother pulling alternator because I noticed a label on it that said "Re-manufactured for AC Delco" so it would seem this has been replaced by previous car owner. Both battery and starter checked out to be good, but of course, they can't test starter under a load.

So, I'm thinking...could the engine be seized, if so, what could've happened? It's never been low on oil and at the early signs of failed intake manifold gasket with only slight external coolant leak, I had it replaced (about a year ago) with the good metal Felpro upgrade kit. But thought I'd better try to turn the crank pulley, just to be sure. Since I had already replaced the spark plugs I was too lazy to pull them out again and figured with the long bar I had, I'd have plenty of torque--couldn't budge the crank pulley though! Removed the serpentine belt to ensure I could spin alternator and AC compressor pulleys (make sure a bearing didn't seize in one of them) and they spun easily, so I am starting to get very worried!

None-the-less, I got a NEW Remy starter and tried again with fully charged battery. At first, just a solenoid click, then after placing in neutral I got a very weak engine turn-over for a second. It sounds just like an engine does with a weak battery, but even with portable battery boost jump--same thing, about a 1 second engine turn-over.

I am nearly at my wits end with this mess. I was hopeful that engine would run better after replacing original spark plugs, but now I can't even get the engine to turn over fast enough to start, let alone run!

Really at a loss and considering having it towed to dealer for diagnosis. Maybe in the morning I'll pull the front 3 plugs and see if engine will crank faster--too much compression for some reason? I honestly can't think of anything else to try!

Any thoughts/insight is greatly appreciated! Thanks, Scott

[Airjer_]

I wonder if you didn't break a camshaft? Its not unheard off.

[manicmechanix]

Sorry to hear that Scott, it doesn't sound good. I think you were doing a good job diagnosing it so far. It should not take a huge amount of force to get the engine to turn over with a long ratchet or breaker bar. Like Airjer said it's starting to sound like the engine is seized probably from a broken camshaft.

I don't want to have you doing more work that won't help, but I have seen starters new out the box that pulled too much current and wouldn't do anything. But I think the next step is to see if you can turn the engine with a long ratchet. If it won't, I think the easiest way to tell if the cam broke is to take the front valve cover off and the rockers and pushrods will probably be slack.

[Scott-Ohio]

OK gents, I've removed the front valve cover and before re-attempting to turn the crank pulley clockwise again (looking at from passenger side fender) I have wiggled/jiggled rocker arms and the only slack found is the 1st and 3rd rockers (left to right facing from front bumper--I presume intake cyl #2 and intake cyl #4) and other 4 rocker arms were tight. Not sure how to check for slack in pushrods since all are surrounded by large springs.

Should I try to turn crank pulley again (with valve cover still off) and check rocker arms for slack again? I was thinking to try with all spark plugs still in, then with front 3 plugs removed. Neighbor said I should probably put trans in neutral too before attempting to turn crank pulley, something about torque converter?

I will anxiously await response from you guys--thanks again. I am quickly approaching my mechanical limits/self-confidence, but need to try and narrow down what kind of expenses I may be facing for this `99 Malibu with 118K miles and also if I should have towed to my mechanic ($50/hour) ~18 miles away or local dealer ($95/hour) ~3 miles away.

Again, I'm very grateful for all your inputs to this thread. Take care, Scott

[manicmechanix]

Originally Posted by Scott-Ohio

OK gents, I've removed the front valve cover and before re-attempting to turn the crank pulley clockwise again (looking at from passenger side fender) I have wiggled/jiggled rocker arms and the only slack found is the 1st and 3rd rockers (left to right facing from front bumper--I presume intake cyl #2 and intake cyl #4) and other 4 rocker arms were tight. Not sure how to check for slack in pushrods since all are surrounded by large springs.

The checking the rockers for slack won't always tell you the cam broke because it may have seized or sheared and then siezed. The thing I was worried about is that it being an interference engine the cam could of seized and valves contacted the pistons, bending the pushrods so there's some slack at the pushrods and locking the motor.

Should I try to turn crank pulley again (with valve cover still off) and check rocker arms for slack again? I was thinking to try with all spark plugs still in, then with front 3 plugs removed. Neighbor said I should probably put trans in neutral too before attempting to turn crank pulley, something about torque converter?

Yes I think you should try to see if the you can get the crank pulley to turn. I would've done that before taking the rockers off. Taking the plugs out should make the engine easier to turn and if it won't then you know the engine is seized.The torque converter should allow the engine to turn even if in Park but just to be safe might as well put it in neutral.

I will anxiously await response from you guys--thanks again. I am quickly approaching my mechanical limits/self-confidence, but need to try and narrow down what kind of expenses I may be facing for this `99 Malibu with 118K miles and also if I should have towed to my mechanic ($50/hour) ~18 miles away or local dealer ($95/hour) ~3 miles away.

Again, I'm very grateful for all your inputs to this thread. Take care, Scott

I think you should see if the crank can be turned. If not then the engine is gone and you might not want to pay more cost just to to be told the same thing. Will the engine turn backwards easier some and then lock turned forward?

[manicmechanix]

Any update yet Scott? Did you get the engine to turn?

[BRAD32]

UNPLUG MAF SENSOR AND START TO TEST.