Changed LIM, now won't idle - GSL-SE
 

This type of stuff happens at the worst time.

So I initially started trying to diagnose a hunting idle issue. I had already changed the UIM's gasket and the problem still persisted, so I recently changed the LIM gasket and cleaned a lot of crud out of the manifold. Now the engine will start, but will refuse to idle without me giving generous amounts of throttle, in which it'll stutter and die out.

I've double, triple checked all the vacuum hoses. I even replaced any I thought may have cracked. I definitely have fuel as I've flooded the engine on a couple of occasions. I still need to check on the spark plugs for wetness.

Other than that I'm at a total loss. I'm 99% positive I've connected all hoses and electrical connectors back where they should go. Any suggestions would be greatly appreciated!

There is ONE vacuum hose which connects to the Dynamic Chamber behind and underneath the BACV fixture on the driver's side. When I did my engine swap, I forgot that one and it was a pain to try and troubleshoot similar issues. That connects to a pipe on the 'spider' which is directly beneath it, and hard to see it's there unless you remove the BACV assembly.

Be sure that one's hooked up, and then start looking at other likely causes of vacuum leaks. Also, if you've not lubed your throttle body rods in awhile, it might be worth doing that - as cold air tends to exacerbate the feedback loop of the throttle body trying to compensate ("surging").

How clean were the gasket surfaces on the engine and on the lower intake manifold? They need to be VERY clean and that old gasket material is extremely difficult to remove. This is why I ask this question, lol.

I know which one you're referring to, I'll have to replace those hoses for peace of mind. I also hit the throttle body and plates with carb cleaner to loosen it up, it's fairly clean and free moving now.

Oh man tell me about it, it was nightmare cleaning that old crap off. I did my best and got it pretty smooth. The manifold side was clean, the engine side was another story. I'll have to revisit it, but I'm not sure what else I can do to get much cleaner than I got it now. Any tips?




Also, last night I pulled the plugs and boy were they nasty and damp. Throwing in some fresh ones tonight and giving it another try.

Got some fresh plugs in and still no progress.

Pulled off the both manifolds again and cleaned the crap out of the engine side. Turns out there was still a good amount of material left that was just stuck on. I took a dremel tool to it with a soft grinder and got the engine to a reflective shine.

After the first start attempt it fired up fine, idled rough around 1800RPMs for about 5 seconds and then sputtered into a stall. So that's some kind of further progress. I might need to order new gaskets as both of them were damp, so they still might not be sealing fully.

I also just tried the whole deflooding trick with removing the spark plugs and the trailing ignition spade with hopes I would push out some junk. Cranked it 4-5 times, then squirted some oil into the spark plugs holes. Wouldn't start this time, so I repeated the deflood procedure but nearly killed my battery in the progress. So in the meantime on I'm standy while my other vehicle charges the battery.

Well now I've somehow gone in the reverse direction.

After letting the battery charge, the no only cranks and will not start. I pulled the ignition spade to deflood and it briefly ran as it burnt off that little bit of fuel. Slid the spade back on and now it still won't start.

How the hell did all this happen just from changing a manifold gasket. Beyond bummed right now.

It could be badly flooded. Try push starting it or find a hill. You'll get 2000 rpm instead of 250 rmp with the battery.

I could try that, but I live up a steep driveway and getting it back in the garage would really suck. If it comes to that I'll do what I gotta do. I may pick up a battery charger and try the spade deflooding method again.

My -SE floods very badly sometimes it will take multiple times of repeating the process so this winter i wired in a switch between the secondary coil spade to the dash so i can deflood without popping the hood and getting in and out a million times. Upgraded ignition helps a load, my -SE's idle improved tremendously after building a new TFI Coil based direct fire ignition (TFiDFIS).

I really like that switch idea.

I bought a battery charger to aid in the deflooding process. Pulled the spade and cranked it for roughly 10-15 seconds 3 times in a row. It still won't start. I'm guessing I just need to keep trying to deflood? Would pulling the spark plugs help at all, and how do I know if it's badly flooded?

I also bought a pair of rebuilt and tested injectors just in case I have one that's malfunctioning.

Did some digging through the FSM and double checked I'm getting spark by grounding the leading spark plug to a ground. Got good spark on both leading plugs, but all 4 plugs smelled of fuel.

While checking the rear leading plug, I left the front plug out and it seems some fuel was still being cleared out, it even shot a small poof of fire out of the rear leading plug hole. My sphincter tightened a bit there lol. So now I'm questioning if I have the fabled leaking/sticking injector. I guess time will tell once I get the refurb'd injectors installed.

Also just for clarifications sake, I see people saying use ATF in the lower holes to lubricate the housings, and a few others saying engine is good enough. I'm trying to oil, just because that's what normally gets injected, just want to make sure that sounds reasonable to you guys.

I still say pull start it with another car. You just need to be quick with the clutch.

DO NOT RUN ATF INTO THAT ENGINE INTAKE! (*well, unless you like a car that smokes from that day forward...).

The 'ATF Trick' may work on an engine that's otherwise seized, but my result was that a non-smoking engine immediately started smoking on startup and then smoking pretty much all the time after running ATF in it to 'clean out the carbon'. In truth, the Oil Control Rings have built up a small carbon ring inside the engine over time and USES this carbon ring to seal for oil control - go figure. Clear that carbon ring out and the engine will suck engine oil through the side seals into the intake side.

That said, the deflood procedure starts by removing the spark plugs. If you're not doing that, you're not really deflooding the engine. Also, know that the fuel that flooded the engine has nowhere to go with the plugs in place except into your engine oil or out the exhaust. The gasoline is thin enough that it will run past the seals anywhere it can, and end up in your engine oil - especially if you're cranking it a lot and building compression within the engine. The point behind using engine oil in the plug holes is to give the engine something more viscous to build compression. You might want to drain some engine oil and see if it smells like gasoline - if yes, change your oil, as the gas will have diluted it sufficiently to kill it's lubricating properties.

If you don't have the patience for this - pull start the car. This builds compression to start and run, because the engine is spinning faster.

A properly setup -SE should never flood. A leaking injector will do it, though. They're not that hard to replace, and you won't know if one's bad until you get it out and send it out to be rebuilt, unless you have a test fixture at home. As another poster stated, installing a 'fuel cut' switch to the coil lead (white wire, which triggers fuel injectors to fire) will effectively shut off fuel flow, and makes a good kill switch if you hide it. Good luck,

Thanks for the info, I'll try a push start if I can get the chance and deflood with the plugs out.

Push start's not fast enough, unless you have access to a football team.

When my original engine died at 220k miles, I cranked and cranked but no compression. Pulled it with a Mazda6 and it spun right over and ran wonderfully. You'll need to pull it with another vehicle.

At this point (it's been a week?), the gas would have evaporated out with the plugs out of their holes. That's the Old Skool method of de-flooding!

Well the refurbished injectors and new UIM/LIM gaskets are installed as well as leaving the spark plugs out for a few days. Still a no go on the starting. Going to to give it a pull start tonight and see how it goes.

Well you guys are hero's, the pull start worked like a charm ofcourse. Funny thing is now I'm back to square one with a hunting idle, lol!

I'm happy to have it idling on it owns again though. Idle troubleshooting restarts tomorrow morning!

Did you adjust the tps to help with the hunting idle?

Looks like a bad BAC valve is causing the idle hunt now. If I pinch the hose going into the dynamic chamber it idles smooth, when I let it go it hunts continuosly.

If you need a spare, let me know. I think I have an extra in my SE parts box.

On the BACV - from "Solving GSL-SE Idle Problems":

"BYPASS AIR SUPPLY
As I said in the beginning, the EGI system varies the amount of air entering the engine to control idle. To do so, it needs a supply of filtered air to work with, and a way to bypass the air around the throttle plates since they would otherwise get in the way. This is what the Bypass Air System is all about.
Following the air funnel (black duct) from the Air Flow Meter back to the engine, you come to a small (about 3/4 inch) tube that connects to a short hose which in turn connects to the Dynamic Chamber. What you can't see is that the tube entering the Dynamic Chamber goes all the way through and exits from the other side into another hose. This hose makes a 90 degree turn and connects to the Bypass Air Control (BAC) valve, so called because the air it controls has bypassed the Throttle Chamber. This is the main device for varying the air supply to the engine during idle. What most think of as the BAC valve is really only the forward half of the mechanical assembly. The rearward half is called the Air Supply Valve, and it only comes into play to compensate for the load placed on the engine when the air conditioner compressor clicks in."

Linked here: SOLVING GSL-SE IDLE PROBLEMS

You'll want to spend time reading through that tutorial if you've not done so already. It has helped me immensely to get the -SE idle circuits tuned well and performing. Try giving the BACV a good cleaning prior to replacement, sometimes you can get carbon fouling inside the Dynamic Chamber that will cake up and cause problems where a quick squirt of brake cleaner will remove it and clear the air paths.

LongDuck, thanks for the link, but trust me I've been all up and down that entire page for the past 2 weeks or so. I had the BAC apart and blasted it with carb cleaner and WD40. It moves freely, but still seems to be the culprit here. I've capped off the ports on the dynamic chamber and BAC for the time being and it idles 95% better than with the hose connecting them together.

The gaskets between the BAC and dynamic chamber is shot, as is the gasket between the BAC and ASV. I believe MazdaTrix has one of them, but not hte other.