Is it a 420a or 4g63? Sounds like possible bad fuel pressure regulator.

Hey DStar thanks for replying, it's the rs 420a motor. Owned it for 21 years now so there's nothing that can go wrong with it that I haven't dealt with before and can fix until now..I hadn't thought about the fuel pressure regulator bc it directly has to do with spark, fuel pumps (I can smelll it)
Once I put the heater on it say 5plus minutes it starts like a champ. At least it runs great and It's not a daily so I don't mind the heater thing except that It's driving me a bit madd not being able to figure out what the hot air is affecting that is causing my car to start, literally has no spark until I place the heater on it

Clearance issue related to ignition.. Does 420a have distributor?
If not check CAS. If you've tested for spark when it's cold and have literally not gotten spark at all then it's def ignition system.
With the cold to hot it's clearance related.
The windings in a bad coil expanding (not likely), distributor rotor to cap (likely), CAS disc (likely), relay (likely). Trace the bases again man. Has to be something like that...

In fact, come to think of it!
My buddy had this blazer one time (we live in PA) and he was having trouble with hard starts, but once it got warm it ran fine. I'll find a picture of the culprit.. Hang on..

The square part (coil?) Was loose enough to cause issues, but once the truck was warm it ran pretty sweet.
Replaced that and it ran sweet. That was a while ago now. Lol.

Not saying this is your issue, but it's possible. Just trying to share my experience. Gut feeling says it has to be something similar...

txbluebeast said:

Car is a 2g RS eclipse with turbo. Has anyone ever had an issue with car not getting spark, it turns over but won't start so you go through the process of checking all sensors and testing coil, asd relay, plugs, wires, replacing parts blah blah blah and accidentally find that if you put a heater on the engine for 5 minutes Viola! The car starts. After running it it will start again but say every morning or after it's sat for a long time no matter what the temp outside is or humidity level It won't start unless I put a heater on the engine for about 5 minutes. It's the strangest thing. I can't pin point it either sometimes I direct the air at the coil and it starts, sometimes at my M&W ignition, sometimes at the engine towards coil and Intake...I'm baffled, can't find anything online so I must be the only one to ever have this issue. It can be a heater or even a hair dryer will work. Any one else ever hear of something like this? Car runs great, very smooth, FP green turbo tuned at 350hp (15psi)for road racing. Just raced last weekend and it's a champ except for that weird thing I wish I could pin point.

Click to expand...

Bleakley said:

Clearance issue related to ignition.. Does 420a have distributor?
If not check CAS. If you've tested for spark when it's cold and have literally not gotten spark at all then it's def ignition system.
With the cold to hot it's clearance related.
The windings in a bad coil expanding (not likely), distributor rotor to cap (likely), CAS disc (likely), relay (likely). Trace the bases again man. Has to be something like that...

In fact, come to think of it!
My buddy had this blazer one time (we live in PA) and he was having trouble with hard starts, but once it got warm it ran fine. I'll find a picture of the culprit.. Hang on..

The square part (coil?) Was loose enough to cause issues, but once the truck was warm it ran pretty sweet.
Replaced that and it ran sweet. That was a while ago now. Lol.

Not saying this is your issue, but it's possible. Just trying to share my experience. Gut feeling says it has to be something similar...

Click to expand...

Says he already did that from what I gather^
420a is a single coil. If I remember pick coil is all within the coil itself.

Coolant temp sensor or intake air temp sensor if it has one would be my first parts to look at

Faulty coolant and intake air temp sensors will not cut spark.
The guy said he's definitely been around the block (21 years - almost as long as I've been alive). I just don't want to see him rule out what I kinda see as obvious (no offense whatsoever OP).
Straight from the FSM.
"1. Engine cranks, but does not start.
(1) Spark is insufficient or does not occur at all (on spark plug).
· Check ignition coil.
· Check crankshaft position sensor.
· Check ignition power transistor.
· Check spark plugs.
· Check spark plug cable."

I'm curious to know what would cause such a special confition though. So if you ever diagnose / fix it def update the thread.
I would even poke at the CAS because you're heat is in that area it seems. And i think that's a mag sensor.

Solved!

Thanks all for responses..it was a hell of a mistery to find. So like I said, went through everything all sensors, asd and fuel relays, went through my MS2 wiring, plugs wires coil, took m&w apart, checked vss (which I had no idea it could mess with your spark) was about to buy new ecu but was sure it was going to be something stupid and cheap and sure enough it was.

My 420a has been turboed since fast furious came out ! I've owned this car for 21 years. Bought when son was born (yep I'm old 40) haha
So apart from the fuel and asd I have these two relays hidden quite well in the back by firewall, after messing with this for months and doing the whole process of elimination gig I came to find out these two relays power up my M&W that I know of but probably also my ecu since the car will turn over without the ecu but won't make a sound with these relays disconnected. These relays are old Bosch style relays, they clicked and everything when ignition key was turned so I thought they were good, somehow they were getting either stuck or just not making contact (who knows) and when I applied heat from heater or hair dryer somehow they were losened up and made contact..the heat gave them a boost hell I don't know but once the car ran for a good while, say the track all day it started every time but otherwise when engine was cold from sitting a while (even a few hours) the relays were staying stuck and not engaging. Car has sat for many years at a time, been a project that I'm just now really enjoying, so I guess things just corrode or start giving up, relays are no exception. So check all relays even the not so obvious ones hidden in the engine bay When all else checks out look for the improbable haha. Thanks again.

Jesus Christ man, that bodykit is one of the very few that actually looks DAMN NICE!!! Props for taking good care of this car for its entire lifetime.

Sorry, I can't help much about your problem but just wanted to share my thoughts on this awesome ride!

Thank you! Yeah she's been taken care of. I appreciate the compliment. Problem fixed btw, some relays needed replacing.

It's a pieced together kit. Stillen front fascia, VIS Racing Evo style CF hood painted to match, fiber glass side squirts, rear fiber glass 98-99 upgraded bumper, Evo 8 wheels, side mirrors are universal after market mirrors, left wing off. It works for me.
.

That's awesome! Thanks for the update, that's crazy. Lol.
To the car - It looks SOO CLEAN. Puts mine to shame SO badly. Lol.

Looks like a mk4 supra kinda, not my taste but it's super clean, props to you. Glad you found the problem too, cant count how many times a relay has been the bane of my existence.

No kidding on the relays:/
Hey funny you make the Supra comment. I was at TWS (texas world speedway) last weekend and another driver walked up and said that my Supra looked nice, I told him it was an eclipse and when he realized it he said "oh shit you're right! Lol thought it was a Supra"
I think it's the body style plus the missing wing that gives it that similar look.