No Start, Need Help!

[GEMELLI]

After more than 3 years of Typhoon ownership, I've finally come across a problem I can't figure out with the search function. I've been member of this forum for a few years, and it has helped me tremendously. Thank you all for that! I'm no professional mechanic, but I can turn wrenches when I have to, so here we go.

I only drive my Ty two or three times a month, and it ran just fine a few days ago when I drove it into town and back. I went to start it yesterday, and it just cranked. I can hear the pump kicking on and priming the system. It had been a while since I replaced the fuel filter, so I did that. Does the same thing. I don't smell fuel on the dipstick or in the fuel pressure regulator's vacuum hose, so I believe the fpr is ok. I hooked a fuel gauge to the test valve and these are the results: Key on engine off, approx 40 psi. Cranking, just under 50 psi. After I stop cranking, it immediately starts to bleed down to 22 psi and holds. I can start it with starting fluid. I've done it a few times, and half the times it has started and idled just fine, driven down my driveway, up to about 15 mph. The other half, it will die as soon as I give it much throttle. This morning, it started right up, but once I shut it off, it wouldn't start again.

There is a CEL when it's running, but I haven't checked it yet. I will now.

I believe it was completely stock when I bought it, so other than a few suspension and appearance mods, it still is.

Thank you for any help I can get!

 

[GEMELLI]

Re: No Start, Need Help!

Ok, I finally got around to scanning the codes a couple hours ago, and they wouldn't pull up. I plugged my scan tool to my 95 Chevy pick up and it pulled the code immediately. I tried half a dozen times, and nothing. I'm thinking it's the oxygen sensor at this point because it's running so rich on start up, but I hate to just throw parts at it when I know there's a code in there. I'll be at it again tomorrow after work, but any thoughts in the mean time would be great.

 

[BoostedSUV]

Re: No Start, Need Help!

try jumping it with a paper clip and count the flashes to pull the code if the scanner isn't working. Would be much easier than thowing parts at it guessing

 

[GEMELLI]

Re: No Start, Need Help!

I completely forgot about jumping A and B! I cleared the codes, then started the truck. The CEL stayed on. I checked the codes and got 34, MAP sensor voltage low/vacuum high. I'll troubleshoot that when I get home from work, but any insight now would be great! Thank you BoostedSUV, for reminding me of the paper clip check!

 

[DaveP]

Re: No Start, Need Help!

Vacuum line for the MAP is disconnected, or split. By far and away the common cause of 34.

 

[GEMELLI]

Re: No Start, Need Help!

Ok, finally got a chance to work on the truck again this morning. On the advice of a fellow forum member, I checked the vacuum line from the MAP sensor. While there were no holes or cracks in the line, it did look as though someone had used some sort of epoxy to "seal" up past vacuum leaks. After replacing the affected lines and checking the surrounding lines, I tried to start the truck again. Nothing. I did get it started with starting fluid again, and it idled just fine. I hooked a vacuum gauge up to it and it read between 16 and 18 inches at idle. The truck idled until it reached operating temperature without issue. I even revved it a few times, with no stumbles. I cleared the codes before I started the truck and the CEL came back on immediately. I checked the codes. Besides 12, the only code was 34 again. I'm at a loss, so I ordered a MAP sensor. Before I install it tomorrow, anymore insight would be very much appreciated.

 

[jaystcb]

Re: No Start, Need Help!

Do you have a wideband, DM or TunerPro?

My Sy did this when I first installed my wideband kit. The exhaust melted the O2 sensor wires.

JUST A THOUGHT... But wouldn't a stuck IAC cause this?

 

[GEMELLI]

Re: No Start, Need Help!

Do you have a wideband, DM or TunerPro?

My Sy did this when I first installed my wideband kit. The exhaust melted the O2 sensor wires.

JUST A THOUGHT... But wouldn't a stuck IAC cause this?

I do not have a wideband, and as far as I know, no other tuner or tuning stuff. As far as I know sounds a bit ridiculous, but I was told the truck was stock when I bought it. I'll double check the ecm to make sure it hasn't been modified.

I thought this may be an O2 sensor issue before I pulled the code, so I physically check it. Everything there is ok, but I will sure check it again.

I hadn't thought about the IAC, but I will definitely check it this afternoon when I get off work.

Thank you very much for the advice!

 

[GEMELLI]

Re: No Start, Need Help!

Yesterday, I installed a new map sensor, and as expected, nothing changed. I reinstalled the original one and went home for the night. This morning, I got back to it. For some reason, I tried to start the truck and it fired right up and idled perfect. I tried a few more times, with the same results. I checked and rechecked the vacuum lines around the map sensor, as well as probed the electrical connections to test them, so I must have corrected a problem then.

However, there's more...

Although it started and idled perfect, it still ran very rich. Even once it was warmed up, it was still too rich. The CEL was still on also. I cleared the codes, and started the truck again. CEL stayed on, just as before. Still code 34. Also, I brake torqued it to see if there were any issues under load. As soon as the vacuum went to zero inches, the engine stumbled and died. I tried it one more time, with the same results.

Like I always have, I will use the search button for these issues, but any help in the mean time would be very much appreciated.

 

[IGottaSy]

Re: No Start, Need Help!

I'd check the ECM connectors for a bad contact or possible corrosion. Also, check the grounds in the engine bay. If your truck will still run, let it come to normal operating temps and then drive it around for a good 20 min driving normally. Then try to boost it up. Maybe the ECM is losing power due to a bad connection/short and must relearn. Hope you fix it soon.

 

[DaveP]

Re: No Start, Need Help!

To me, the fact that "it fixed itself" indicates that this is an intermittent electrical connection.

What bugs me is that Code 34 is High Vacuum. High vacuum makes the system go lean, not rich. So the Code indicated, and the symptoms don't go together. What are you seeing that makes you think it's "running rich"? Smell? Black Smoke? 34 and Rich do not go together.

You could unplug the hose on the MAP and fire it up. It will be rich as hell, but it should set a code 33. See if it does.

Also, I brake torqued it to see if there were any issues under load. As soon as the vacuum went to zero inches, the engine stumbled and died. I tried it one more time, with the same results.

If the vacuum goes to Zero very quickly, I wonder if you have a plugged cat or exhaust system?

There's some more ideas, but this isn't making sense.

One correction: Engine off, key on, with a 2BAR MAP (Stock) MAP voltage on the lt green wire should be 2.5V. ( I may have said 4.5V, which is true for a 1 BAR, but incorrect for a SyTy). For a 3BAR it's 1.6V. I suppose it may be possible to set 34 by using a 3BAR MAP on a system that wants a 2BAR. But I think you said you have 2.5V engine off. Which IS a 2BAR. Recheck it by probing the lt grn wire to ground with everything hooked-up. Use a drywall screw to pierce the insulation. They work well for this. Another indication of a 2BAR is the stock boost gauge will read center scale with engine off.

Good Luck.

 

[GEMELLI]

Re: No Start, Need Help!

I'd check the ECM connectors for a bad contact or possible corrosion. Also, check the grounds in the engine bay. If your truck will still run, let it come to normal operating temps and then drive it around for a good 20 min driving normally. Then try to boost it up. Maybe the ECM is losing power due to a bad connection/short and must relearn. Hope you fix it soon.

I didn't have a chance to work on it today, but as soon as I get some free time, I will check the ECM connections and the grounds in the engine bay. I will also attempt to drive it around and allow the computer to relearn. Thank you so much for the advice!

To me, the fact that "it fixed itself" indicates that this is an intermittent electrical connection.

What bugs me is that Code 34 is High Vacuum. High vacuum makes the system go lean, not rich. So the Code indicated, and the symptoms don't go together. What are you seeing that makes you think it's "running rich"? Smell? Black Smoke? 34 and Rich do not go together.

You could unplug the hose on the MAP and fire it up. It will be rich as hell, but it should set a code 33. See if it does.



If the vacuum goes to Zero very quickly, I wonder if you have a plugged cat or exhaust system?

There's some more ideas, but this isn't making sense.

One correction: Engine off, key on, with a 2BAR MAP (Stock) MAP voltage on the lt green wire should be 2.5V. ( I may have said 4.5V, which is true for a 1 BAR, but incorrect for a SyTy). For a 3BAR it's 1.6V. I suppose it may be possible to set 34 by using a 3BAR MAP on a system that wants a 2BAR. But I think you said you have 2.5V engine off. Which IS a 2BAR. Recheck it by probing the lt grn wire to ground with everything hooked-up. Use a drywall screw to pierce the insulation. They work well for this. Another indication of a 2BAR is the stock boost gauge will read center scale with engine off.

Good Luck.

I agree completely about the truck "fixing itself". My Lightning does that sometimes, and it bugs me every time. I suppose it's possible that the electrical connector at the map was somehow messed up and by back probing it, the affected wire went back into place. I will look into that possibility asap too.

It didn't make sense to me either, that the code and symptoms didn't match. I'm basing my assumption that it's running rich only off what the exhaust looks like and smells like. It's not black smoke, it looks more like steam, and there is a lot of water vapor coming from the tail pipe. Enough to puddle up on the floor. It's not antifreeze though, just water, and there is a 50/50 antifreeze/water mix in the cooling system. The exhaust smells like gasoline, however, much less so once the truck warms up.

As soon as I can get back to it, probably after work tomorrow, I will unplug the vacuum line from the map and recheck the codes.

I was fairly sure that it had a stock map sensor in it, and your voltage information confirms it. Thank you for adding that! The boost gauge is centered when the engine is off. I will recheck that reading as soon as I can and report back.

 

[GEMELLI]

Re: No Start, Need Help!

If the vacuum goes to Zero very quickly, I wonder if you have a plugged cat or exhaust system?

Oops, I failed to address this.

It doesn't really go to zero any quicker than it should. The speed at which it goes to zero is dependant on how hard I press the throttle. Forgive me if I'm misunderstanding your comment.

 

[Don W.]

Re: No Start, Need Help!

Side note on the MAP sensor: On my truck those wires and hence the plug had a lot of strain on them. Check that the plug is fully seated with no pull on the wires.

 

[GEMELLI]

Re: No Start, Need Help!

Yesterday, after work, I unhooked the battery and left it over night. I got a chance to work on my truck for about an hour today. I wasn't able to try all the suggestions, but I did get to some of them.

I pulled the vacuum line off the map sensor and tried to start the truck. At first, it wouldn't start, and once it did, it ran as expected for a few seconds, then died. I checked the codes. Still only code 34.

I'd check the ECM connectors for a bad contact or possible corrosion. Also, check the grounds in the engine bay. If your truck will still run, let it come to normal operating temps and then drive it around for a good 20 min driving normally. Then try to boost it up. Maybe the ECM is losing power due to a bad connection/short and must relearn. Hope you fix it soon.

I didn't get a chance to check the ECM, but I did let it warm up and drive it around my driveway. My driveway is pretty big and has a straight stretch where I can get up to about 15 mph. It stumbled a lot below about 2000 rpm and did not want to run after zero vacuum. I drove it for about 15 minutes, and the last thing I did was brake torque it. It died and wouldn't restart, so I pushed it back to my shop. After a few minutes, it started right back up, but wasn't idling great. I goosed the throttle and it died as it tried to settled into an idle. I let it sit for a few more minutes, and it started right back up. I goosed the throttle again and it was rough, but didn't die. The exhaust smelled almost normal after I drove it around a bit, but did get a faint smell that made me, and a Mercedes technician friend of mine, think of the cat.

I know I'm giving you guys a lot of probably unnecessary info, but I want to be thorough.

Side note on the MAP sensor: On my truck those wires and hence the plug had a lot of strain on them. Check that the plug is fully seated with no pull on the wires.

I did check this and there is enough slack in the wire to allow the connector to seat fully. Thank you very much for the thought!

At this point, I'm going to do a tune up, since it's been a year or so, and seems to be stumbling when it is running. With all the moisture in the exhaust, it seems the cat is doing its job, but based on the smell today, it may be time to replace that too.

 

[GEMELLI]

Re: No Start, Need Help!

Ok, I've done the cap and rotor, and the plugs. The wires looked good, but I ordered them too, just in case. Exact same results. The truck starts right up when cold, but will not run once the boost tries to kick in. Once it's warmed up, restarting is hit and miss. I rechecked the vacuum lines and found no issues. The MAP sensor is good. The fuel pressure is good. I've cleared the codes again, and code 34 is still the only one thrown. Just a reminder, code 34 is MAP sensor voltage low, vacuum high. When the truck is running, it still runs rich.

I'd rather not bring it to the shop, but I'm at a loss. I really appreciate the help so far, but I think I need a bit more.

 

[DaveP]

Re: No Start, Need Help!

By chance, you're not in SoCal are you? It's so difficult to follow someone else's troubleshooting methodology through the monitor and keyboard.I read Code 34 again.

A code 34 will set when:

• MAP signal voltage is too low. (It does not stipulate a value)
• Engine speed below 1200 RPM and/or TPS greater than 20% (right about 1.3 Volt)

A loss of the 5V voltage at the MAP (gry wire) would cause MAP voltage to go low, and set 34.

Have you checked TPS voltage? The voltage on dk blue should be about .5V at closed throttle. If it is high during cranking, the system enters "clear flood mode" and delivers no fuel to clear the flood. This could be the source of the intermittent no-starts. It could also be the source of the 34 if TPS is affecting the code 34 diagnostics.

I once had a bad ground connection at the TPS on one of my L35 CPI cars. The loss of ground would send the TPS to max 4.5 voltage. Ie, WOT. It wouldn't start, idled fast, and wouldn't shift out of 1st (electronic trans) all because the system thought the throttle was wide open. It only took me an hour to find, but I substituted some parts from my other car before I zeroed in on the actual problem. Bad connection at the TPS connector itself.

I still feel this is an intermittent electrical problem. Because it comes and goes. You'll get it, and when you do, you'll say "that's IT? Wow, that was easy".

 

[GEMELLI]

Re: No Start, Need Help!

I'm not in SoCal, but right about now, I sure wish I was. I was working out of town for a bit, but I'm back to it now. I will check the TPS when I officially wake up in a couple hours. You're right, this is something simple, and I will laugh about it later, but it sure is frustrating now. I think I may be dealing with two issues... one intermittent electrical issue and a vacuum issue that's causing the truck to cut out when the boost tries to kick in. Maybe I'm missing something, and I probably am, but that seems vacuum related to me.

As far as the MAP voltage, I'll check it again, but I believe I got approx 2.5v when checked, not 5v. I'm sorry, but I'm not super familiar with what wire should have what voltage, but I'll check into that while waiting for your answer. Thanks again Dave!

 

[GEMELLI]

Re: No Start, Need Help!

I must have missed something the first ten times I looked over the vacuum system, because the no start condition seems to be resolved, but I've started a new thread to deal with just the dying under boost issue.

Here's a link.

http://www.syty.net/forums/showthread.php?t=92222