86 GXL with engine from 86 base. Installed S5 UIM and blocked off emissions while engine was out.

I've been working on it for the last couple of weeks and now it starts and runs. If I crack the throttle, it runs rock-solid at 1000 rpm.

Yesterday I found out the dynamic chamber and a vacuum hose were leaking, so I fixed them and fired it up. It idled by itself, pretty shittily, but it was trying...around 500 and it was stumbling a little bit.

Took it for a drive around the block and it died again when I took my foot off the gas. When I got back, it wouldn't idle on it's own, and there was smoke or steam?!?! coming out of both ends of the upper radiator hose.

Bad idle - MORE vacuum leaks? bad tps? (should be fine and adjusted, worked on old car just fine)

Steam from radiator - plugged coolant overflow line? I really have no idea.

i'm frustrated. please help.

 

have you compression checked the engine?

 

I checked it before pulling it from the old car. Both rotors were good (95-ish) with the back one being a little low due to a stuck seal.

When first turning the car over and trying to start it, I heard 5 strong pulses. I tried unflooding it using ATF and now I have 6 strong pulses, I must have unstuck that last seal. I'm convinced compression is fine. When it runs, it runs strong.

 

well from what i herd 95 is on the lower end. it should be uward near 105 since its an older engine for it to be strong.

 

It's low, but it's fine. That's not the problem.

I should also mention that it's pulling 15 mmhg vacuum at idle...not great, but not horrible.

 

have you pressure tested your cooling system?If i recall 95 is decent compression... its anything thats under 85 that is probably on its way out. 120 is basically max and 100-115 is good compression.

 

I have not pressure tested the cooling system, perhaps I should...


I'm wondering if maybe the LIM>engine gasket is leaking.

It's brand new, from mazdatrix, i believe the part is 13-111A-N326.

I didn't put sealant on it....are you supposed to?

 

^ its a good idea but not necessary. Did you replace the o rings between the LIM and block?

as far as i know, it sounds like a bad coolant seal, i don't think that the water pump creates enough pressure to blow steam out of the rad hoses unless they are loose... it sounds like cobustion gasses making their way into the cooling system. However i am no expert.

 

The O rings come on the gasket.

I thought about the coolant seal, i'm kinda hoping that's not it for obvious reasons.

 

pressure test...

i didn't know the o-rings came on the gasket, i didn't see that it was n/a.

 

update:

I ran over to Autozone and got their radiator pressure tester...but it's got the wrong adapter on it and they don't have the right one. I can test the cap, but not the cooling system

so, I did the poor man's coolant seals test. I ran the engine at idle and checked for bubbles. NONE. Then I revved it, and the coolant level in the neck went DOWN, not up, so I think the coolant seals are fine.

someone give me something to check, i'm getting furious at this thing.

 

Check the idle FAQ thread.

 

I took a glance through it, found here

https://www.rx7club.com/2nd-gen-archive-72/faq-idle-problems-334730/

The car has to idle for most of those adjustments to happen.

 

Did you make sure the intake hose is on properly and clamped and the TB elbow is tightened properly
I went through a ton of **** once because my TB elbow came loose.

 

Haha, I did have a problem with that, so now it gets tightened TIGHT. I've been pulling the elbow on and off to swap on my pressure tester elbow.

Besides, that would be a metered air leak, not a vacuum leak.

 

 

You get it figured out?

Tim