2003 protege5 dies if i dont give it gas

J

jonathan62019

Member
:
2003 mazda protege5
2003 mp5 5 speed. 2.0 all stock. it starts up then dies. unless i give it gas to keep it above 1k rpms. the codes that it throws is po102 po103 i also have a 2002 mp5 so i switched my MAF out of my great running 2002 into the 2003. and it still throws the same codes. I can unplug the MAF on the 2003 it doesnt fix the idle and believe it or not it will still rev and not stall out with the MAF unplugged. anything out there cus a MAF code to throw with a good MAF or why my car dont stall out with the MAF unplugged? runs great going down the road. im at a loss. only thing i can think of is broken wire. but i get 12v going through the power wire and the other 2 wires seem to be grounded good. so maybe bad ECU? i dont even know if i posted this in the right spot hehe sorry
 
Update. Switched the ECU from good running one to bad running one and no difference. So ECU is fine. ... The guy i got it from did put a new head on it. All new valves cams everything. I wonder if he messed up the intake manifold gasket????? Or would that just make a high idle..?
 
P0102/P0103 OBD-II Trouble Code

*Mass Air Flow (MAF) Circuit Low Input
Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. A more technical description would be that the MAF circuit had lower than expected voltage (air flow).
(Read more at: http://www.obd-codes.com/p0102 Copyright OBD-Codes.com)

"lower than expected voltage (air flow)" you could have a vacuum leak after the MAF, which would pull more air from the leak than from before the MAF, causing it to read as low air flow. i had a vacuum leak and rpms would drop very low at idle and the engine would stall, unless i gave it gas
 
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Yeah im pretty sure its a vacuum leak. Because i get no codes now. But still dies at idle. Put 200 miles on it with no codes popping up or pending codes. I replaced the tps and iac with the good ones on my other mp5 so ive tested or changed every sensor lol next ill see if i have intake gasket leak. If i can find my propane bottld
 
Ok so did the propane bottle leak test and cigar smoke leak test. No leaks. BUT!! I dont think any air is getting through my throttle body when foot isnt on the pedal. The hose that goes from the driver side of the valve cover gasket to the intake tube. I used that one last to check again. And i blew through it and i couldnt blow at all. Air wasnt grtt passed the throttle butterfly. ..... So i tested that same scenario on my good mp5 and when blowing on that tube you could clearly tell air was flowing like it should. Sooooo i am going to take throttle body off. And see what the heck is going on. Clogged ports im guessing
 
The throttle plate should make a seal against the throttle body when closed. At idle, air passes through the bypass holes that are machined in the throttle body on the air filter side of the throttle plate, which are metered by the IAC.

Even if you replace the IAC, if there is a blockage in those holes or the IAC bore, you will have idle problems.

I would pull the TB completely off, remove the IAC, and check those holes.
 
Agree with Mr giggles. I'd vote iac, sounds classic iac trouble to me.

Get some throttle body or carb cleaner, a clean rag and an old toothbrush. Spray the throttle body liberally, let it sit for a quick minute and clean that sucker until.it it shines. And make sure all the holes between the iac and TB are clean and clear too. While you have the iac off it doesn't hurt to give it a good scrubbing but generally if the valve is sticking it needs to just be replaced.
 
i pulled throttle body and the iac ports are clean as a whistle. i did pull egr and deleted it with some sheet metal. it got dark so ill put all the cleaned up parts on tomorrow after i get a gasket. for TB think a clogged or halfway faulty CAT could cause the stall problem? the only other problem it has is it smokes real bad when its a cold start. i was thinking valve seals but it has a brand new head on it with all new parts. was thinking rings but it has great compression. and stops smoking after about 20 seconds. meh im guessing i bought someone else's headache :p
 
Smoke ok cold start is either headmaster issue or valve seals, depending on the color of the smoke. I'd bank on valve seals. Just because someone rebuilt the head doesn't mean they necessarily did it right... and rings will usually smoke on acceleration or while idling all the time, not just a cold start.

If the cat is clogged it usually won't run at all, but you could always unbolt the exhaust before the cat to test that. Don't have to pull it all the way off just loosen the bolts enough to create a nice pre cat leak.

How caked up was the TB with carbon build up before you cleaned it up? If it was really bad I'd still bet on IAC related issue.
 
jonathan62019 said:
i... was thinking rings but it has great compression. and stops smoking after about 20 seconds...
Click to expand...

Sounds like oil rings to me.

The oil rings like to seize up on our FS engine.(really tiny oil drain holes)

Google seized oil rings.

There's a simple test... Remove you're spark plugs before a cold start.

If there's oil on the pistons you have bad valve seals.

If not, replace your plugs then start your engine and run it for about ten seconds.

Remove the plugs again and check for oil.

If the pistons are wet, then you have bad oil rings.
 
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Inside the IAC was really clean and throttle body was clean except the backside of the butterfly. Yeah it was a reman head came with all the stuff preinstalled.. I dont really care about the oil smoke on start up lol i just want this thing to idle. I could check the volts going to the iac. Maybe its not getting the full 12v and its not opening. Wish this thing would just throw me a code lol whats the point of having obd2 if it dont work haha
 
got it all back together. took a break to eat some breakfast at 1pm lol i was thinking too about the piston rings. wouldnt it be unlikely that all 4 rings fail at the exact same time? seize all at the same time. that would be really bad luck. after i get it started i will have to drive it around the block a few times to let it warm up then let it get cold again because i did a few cold starts on it so im sure there is oil still on the pistons., hopefully the fully cleaned throttle body will fix the idle. if not then i have zero ideas left
 
ok got it back together it idled at about 1400 rpms for id say 15 seconds pretty smooth and then it started doing the exact same thing. just falls on its face. lame...
 
i held the vics open and no change and made it say close and it didnt change anything. dont know if thats how i test it or not haha
 
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Ok so i drove it for an hour last night so i seen no smokem i woke up this morning. Pulled plugs. I couldnt see down in there so i used a long piece of plastic and when i pulled it out there was oil dripping off of it. :/ so valve seals. Makes me wonder with it being a newly reman head what else is messed up and maybe why it wont idle? Lol i am using my phone so idk if this font im using just looks big to me or if it really is big. Wont let me change the font.
 
if i pull the brake booster hose on my 2002 MP5 it idles real high. i pull the brake booster hose on my 2003 ( one with idle problem ) nothing changes. but there is vacuum to it.
 
Sounded like valve seals from the beginning ;)

Only choice really is to replace them, i bet they either weren't replaced, or were installed wrong when they "rebuild the head". This means a lot of things to a lot of people... To me, it would mean machine/replace/respec everything like new. To some people they'll lap the valves and call it a day. Some will just clean it up (if a sludge issue is the reason for a rebuild) and slap it back together and never even pull the valves out. Some will just replace any bad valves if a valve issue is the reason, but not touch any of the good ones. Depends on the tech and the day they were doing the job. Or there's the possibility one of them was damaged during installation as well. If you're only leaking into 1 cylinder this is a good possibility. If you're leaking into multiple cyl's then they probably didn't replace them or used the wrong ones (aftermarket parts aren't ALWAYS 100% correct, regardless of what the box says...)

And before digging too deep, i'd check all of the vacuum lines to make sure they're hooked up correctly. Also check any electrical grounds. You've got an advantage because you have 2 of these cars, so you have a known good to compare to. Sometimes something silly will cause big problems.

Also, there's the possibility that it may be a timing issue. IF someone "rebuilt" your head and you've got valve seal issues I have to question their quality of work overall. there's a good possibility that they did something else wrong while they were putting it back together. These cams have a tendency to "jump" real easily if you're not careful. Anyone that's replaced a timing belt before can tell you that the cams tend to spring to where they're happy. For some reason, the "sweet spot" to set up the timing belt correctly isn't exactly easy to hit, it has to be on juuuust right or it'll be off a tooth when you spin the motor over and recheck your timing marks.
 
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