I have a 1995 Talon, just bought it, non turbo obviously. The problem I'm having is that the car has a really hard start. I usually have to turn it over several times, and putting the gas pedal to the floor seems to help. I am getting a code 23 and 25 (23- air intake temp sensor, 25- target idle not reached). There is no air intake temperature sensor. I'll pick up a new one, but would this cause my car to start so hard? Once started, the car seems to run/drive fine, but I haven't driven it much because of the issue starting it.

This is what I have done so far:
check for fuel and spark
clean IAC
replace fuel filter


The car has a built engine, it has 272 cams in it, a Venom intake manifold, and a Modern Performance throttle body. These are the aftermarket parts worth mentioning, as they may or may not be relevant to the issue I'm having.

Any help that anyone can provide will be very appreciated. This is my only car, and not being able to use the car is becoming quite problematic. Thanks in advance!

The intake air temperature sensor is on the back of the stock intake manifold - not sure where you would have it on your venom but it is a 1/4" NPT sensor if I recall.

Another cause of prolonged cranking before starting is a disconnected or bad cam shaft position sensor.

Code 25 also can mean an IAC problem.

272 Cams huh? I would like some proof if you do not mind. Manufacturer? Part number? Unless it was a custom grind it is highly unlikely you are running 272s.

Would the lack of an air temp. sensor cause the car to start so hard? The cam position sensor is plugged in and the wiring seems fine, if the sensor itself was bad, wouldn't it throw a CEL?


272 Comp cams was what I was told were in the car when I bought it. If they don't exist or something, I suppose he could have been lying. I am working on getting in touch with the guy who actually built the motor, I'll see what he says about it at that time.

Originally posted by s.wilson
Would the lack of an air temp. sensor cause the car to start so hard? The cam position sensor is plugged in and the wiring seems fine, if the sensor itself was bad, wouldn't it throw a CEL? 272 Comp cams was what I was told were in the car when I bought it. If they don't exist or something, I suppose he could have been lying. I am working on getting in touch with the guy who actually built the motor, I'll see what he says about it at that time.

Hmm. Are you sure you are missing the sensor? Or can you just not find it on your intake? You should have a sensor on the back of the manifold (in line with a couple of vac ports). I can't imagine that she would run fine without it.

Though I have never done it, I would imagine that it would cause constant rich conditions with the ECU going to a default setting. Either way, you need to address that cel to get a base to work off of.

And you will find that you do not have 272's in there. You bought your car from a 4g63 guy who just threw that number out because they use them in 4g63's. But maybe you do have some Crane's or Crower's in there (for our car) and the guy was just talking out of his ass.

Depending on the temps at your house/state the car will run ok without the sensor however starting will be an issue.

Since you hold down the pedal and its better indicates its running very rich.

With the sensor removed the ecu thinks its -40 air intake temps. The ECU will add shit loads of fuel.

Okay, this makes sense, it seems like it's really rich when starting, and the gasoline odor is really strong. I'll get on that temp sensor tomorrow then. I'm in MI, it has been cold, but the last couple days were at about 40*F. Not too cold.

Ok, that would explain why you think it runs fine. Its prolly running rich but not so rich your coughing at the tailpipe. I take it mileage isnt great either?

It starts so unreliably that I don't drive it. It's literally been a garage whore since I bought it. I took it to the gas station up the street, that's it. It's definitely running rich, but it seems to idle out and rev okay for the most part. I'll figure out what's up with that sensor tomorrow. I was thinking of the battery temp sensor being missing, not the intake air temp sensor, so I'll find it and see what the deal is. It looks like they are only $15 or so from Autozone, so I will most likely just grab a new one. I'll post an update once that's done. Thanks guys!

no 2GNT ever came with a battery temp sensor.

Battery temp is determined by the impedance of the battery.

Oh, I have a wire just hanging there by the battery, I assumed it was a temp sensor because I used to have a DOHC neon, and it had a temp sensor on the battery tray. It looked like it was the same thing. Guess that's what I get for assuming...haha. Any ideas on what that wire is? I'll take a picture of it in a few hours.

If i recall only the 95 neon had the temp sensor.

A picture would help.

Just to clarify, it may actually have 272's in it.

Delta Camshaft can make them, and DSM Graveyard is releasing theirs the end of next of week.

I had a long conversation with Delta yesterday.

Okay. I found the air temp sensor, it's there, but the wires were frayed. it looks like to fit the venom intake manifold, the back part of the plastic clip had to be removed, and there was bare wire. I used some liquid electrical tape, separated the wires from each other, and closed them up. I reset the computer, and tried starting it. It's still starting hard, and I'm getting codes 12, 23, and 55. Obviously, 12 and 55 are unimportant. Code 23 - So there's still something up with the Intake Air temp sensor. I'm going to go ahead and grab a new sensor, since it's only like $15.

Also, pictures of my missing electrical components. If anyone can help me identify these, that would be great. They were missing when I bought the car, and they don't seem to be throwing any codes.

Do you have a windshield washer fluid reservoir on the firewall still? If not the bottom one resembles the connector for the washer fluid pump.

I don't have the washer fluid tank, so that explains that. I actually think I have a spare one laying around, maybe that gets thrown in this weekend too.

Is failure of the intake temp sensor common on these cars? The sensor itself looks like it's in decent shape, but I know that doesn't necessarily mean anything. I just don't want to spend a ton of time and money following dead end leads, and from what I've seen and read thusfar, the 2gnt group seems very knowledgeable and experienced.

Not that I can recall. If you said the wires were frayed or the clip was damaged it may be that the pigtail needs to be replaced rather than the sensor.

Remove the harness from the sensor, and probe the ends of harness with the key in the ON position to verify you have a ground and voltage source.

The 1st plug appears to be the speed sensor plug. The second one is not the washer resevoir. That plug is in front of the trans, how would the washer resevoir be all the way up there? Not sure what the plug is, i have never seen one like that so it makes me wonder if that was part of the secondary injection setup that was removed by a TSB. Perhaps someone who has removed it can chime in.

Originally posted by Star Turbo Talon
The 1st plug appears to be the speed sensor plug.

Agreed. VSS down by the back roll stop motor mount. On top of the differential.

The second one is for the EGR I believe. Here's a pic of mine on the 96;



I'm pretty sure that I have an EGR valve off a junker that has that connector on it. It connects up to the black valve on the front of the engine (it has a tube that runs back to your.....Wait, I'm guessing with the Venom, you may not have it).

Yeah Mark your picture looks much better....lol Def EGR plug and the venom doesnt have provisions for the EGR tube.

Originally posted by s.wilson
I found the air temp sensor, it's there, but the wires were frayed. it looks like to fit the venom intake manifold, the back part of the plastic clip had to be removed, and there was bare wire. I used some liquid electrical tape, separated the wires from each other, and closed them up.

Just because of the problems in fixing this, I have suspicions in this area ^^^ I'm thinking I would cut off that clip and re-do the connections with at least butt connectors and heat shrink. It is possible that there is a problem in there still.

Oh yeah, you aren't dyslexic are you? That would explain the 32 becoming a 23 :P

It really needs a whole new pigtail to be completely right. I don't know where to get one though, and it's getting voltage? The wires aren't touching and aren't bare anymore, but it still isn't much to look at. Should I go ahead and swap my injectors? I have another set laying here...

Also, it seems like it starts harder after I have let it run already. It doesn't matter if it runs for 10 seconds or half an hour, but it starts a bit easier the first time than the 2nd or 3rd.

Originally posted by teklein
Just to clarify, it may actually have 272's in it. I had a long conversation with Delta yesterday.

Its also possible that I will hit powerball, but not likely.

Funny, because I just had a conversation with "my buddy" Ken over there, lol. He couldn't make the numbers I needed. With my duration at around 262 I was over 500 lift by his numbers. That's probably going to hit my piston no matter how I have them made up. Though he did say that he could make a copy of a crane 28. Which seems a little weird because their numbers are around 256 duration with 496ish lift. And yet he couldn't generate something close with his math (not doggin him, just curious).

But yeah, the countless times that I have seen the 4g63 guys sell their 420a's with a 4g63 grind claim vs the "never" times I have seen an actual 272 made for a 420a; my money is on the 4g63 "claimers".

Okay, I'm going to reconnect the speed sensor right now.

I tested voltage to the temp sensor, 5 volts on the dot. I tested resistance through the sensor, I don't recall the number, but it was within the spec provided in this site's wiki.

I reset the ecu, the car is still starting really hard (if at all) and I'm not getting codes 23 and 25. I'm getting pretty desperate here, if anyone has any more ideas. Thanks!

Originally posted by bullettdsm

Originally posted by teklein Just to clarify, it may actually have 272's in it. I had a long conversation with Delta yesterday.

Its also possible that I will hit powerball, but not likely. Funny, because I just had a conversation with "my buddy" Ken over there, lol. He couldn't make the numbers I needed. With my duration at around 262 I was over 500 lift by his numbers. That's probably going to hit my piston no matter how I have them made up. Though he did say that he could make a copy of a crane 28. Which seems a little weird because their numbers are around 256 duration with 496ish lift. And yet he couldn't generate something close with his math (not doggin him, just curious). But yeah, the countless times that I have seen the 4g63 guys sell their 420a's with a 4g63 grind claim vs the "never" times I have seen an actual 272 made for a 420a; my money is on the 4g63 "claimers".

Maybe so, but my point was that it is *possible*.

Originally posted by teklein
Maybe so, but my point was that it is *possible*.

lol, true dat!

Should I go ahead and pick up a new AIC? They are only $20 new, shipped off eBay. I cleaned it, reset the computer, and the code came up again after trying to start. Would a bad AIC possibly cause the car to start hard?

do you by chance live in michigan? i think i may know what car this is....

95 eagle talon painted black? body kit? blue aem adjustable gears? polished venom mani? mirror black valve cover?

a guy i know was recently selling this here in michigan. lives in warren. the reason this post grabbed my attention and made me think so was he was talking about it having 272 cams.

EDIT: yes this is the car. i didnt see your new to the site post which has pics til after posting this. welcome to the board!

Yeah that's the car. It needs a lot more work than the previous owner told me, but I'm just gonna play the hand I was dealt. I've always liked these cars, so I'm just going to do what I can to bring it back to its full potential.

"car takes a few times to start i was told cause high lift on cams"

Words from the previous owner. Any ideas here? New IAC going into the car tomorrow. Still getting a code for the AIT. How confusing.

I run a pretty high lift cam (.444" / .437") and mine fires up with a flick of the key.

Yeah, I figured that the line about the cam lift was just some crap that was easier to say than to fix the real issue.

Start checking fuel pressure as well as compression.

Spark quality will make the car hard to start as well as injectors that are clogging.

Oh, new plugs going in after work today with the new AIC. Forgot to say that. I pulled the current plugs last night and they are black and were wet with gasoline.

How about the coil and wires? What kind of condition are they in?

Resistance is good through the coil according to the tech sheet in the wiki. I didn't test the wires, but I tested for spark.

Resistance doesnt mean shit. A fouling wire will test fine.

You could have injectors that are leaking.....Not clogged sorry.

Okay, new plugs and new AIC. Started a liiiitle easier. Not much. Reset the computer and pulled codes. Just getting a 23 now. I still can't figure out why I'm getting that code. A leaking injector wouldn't throw a CEL? I'm not looking forward to pulling injectors with the Venom intake manifold, haha. I guess if I have to, I will, but...

Terry may be onto something. I believe a leaking injector will cause rich conditions. Smell your oil. If it smells like gasoline you may very well have a leaking injector.

You could have crower 2s, they are popular with the 420a.

Yeah, I'll pull the valve cover and look for a part number someday. But right now I just want the damn thing to start when I turn the key. It doesn't seem like too much to ask, but apparently, it is. hahaha, is my frustration starting to show?

Update: So now I guess I'm just chasing sensors. Everytime I replace one, another one is bad. The car starts fine when it's cold now. Starts great. But once it warms up, it stalls, and when I try to start it, it fires 1 time then quits.

Today, I replaced the pigtail for the AIT, reset the computer, car started right up. I shut the car down after it warmed up, and when I tried to start it back up, it just turned and turned, but wouldn't fire. I threw a code for the coolant temperature sensor, so I ran to the store and picked up a new one. Installed the new CTS, the car started right up. Once it got warm, the car stalled, and each time I tried to start it, it fired once and then quit. I pulled the codes, and got a 21. Time for new O2 sensors?

Alright, another day, another failed attempt at getting this thing going.

When I go to start the car, it cranks once, fires right up, but then immediately dies. I swapped in another '95 PCM, no help. I also checked power to the crank and cam sensors, 8.something volts. I'm only getting 12 and 55 when I keydance.

Any ideas? I'm at a standstill here.

Problem Resolved. Apparently the safc wasn't wired very well. I pulled it out and the car is starting and running fine. I'm still throwing a 21 (o2 sensor) and I tested voltage on the upstream, so I know it's the downstream. That's a problem for another day, I'm just excited to have my car going.

THANKS everybody who contributed, I really appreciate all of the help and support that I recieved!

Nice man, glad to hear you got it running correctly. Downstream 02 is not as important as the upstream, but I would still change it out if I was you.

Originally posted by s.wilson
Problem Resolved. Apparently the safc wasn't wired very well. I pulled it out and the car is starting and running fine. I'm still throwing a 21 (o2 sensor) and I tested voltage on the upstream, so I know it's the downstream. That's a problem for another day, I'm just excited to have my car going. THANKS everybody who contributed, I really appreciate all of the help and support that I recieved!

I win.

Haha yes you win. I'll come up with a prize of some sort lol. She fired right up after I pulled the afc out. Drove it around last night just fine. And, yeah I will swap the downstream, maybe this weekend or next week.

You didn't know it but I was a close second, lol.

I'm thinking that was a little tid bit of info that you probably should have shared. But great that she's running nice again.

Originally posted by s.wilson
I'm still throwing a 21 (o2 sensor) and I tested voltage on the upstream, so I know it's the downstream.

Again I would not rely on CEL codes, you need the P0xxx code as it will tell exactly what is wrong with the sensor, and what sensor to look at.

There are separate codes for the heater circuit, and open signal, shorted signal etc.

Yeah, yeah. The safc wiring must have gone haywire while I was working on replacing sensors, because it was fine before, it just started doing that 2 nights ago. And I was told that the symptoms sounded like no map signal. So I pulled the safc, and it's all good.

My diagnostics port doesn't seem to work, so using a scanner isn't really an option for me. I'll just replace them both. Why not? Every sensor on this car was junk anyways, why would the 02's be any different. lol

Sometimes the early production 95's need a little playing around with to get a code reader to work. My 95 eclipse has to have the engine running and tell the reader that it's a 96 for some stupid reason. My friend's that's only a couple months newer works only with the engine off and telling the reader it's a 96

95 ecu's aren't very consistant.

I'll try that, my friend has a Snap-On Solus? I think it's called Solus, anyways, it's a pretty nice looking piece, supposedly very expensive, and I have full access to it, that is, if I can get it to work. haha.

I'm having another issue now though, stuttering and hesitation from around 2k-4k in my rpm range, although I didn't take it above 4k to see what happened. If I give it full throttle, it feels like the engine completely dies. And I feel like I get a decent misfire, as well.

But, if while driving, I click the key off then back on, it starts running fine for a few minutes, before starting the sputtering again. Any ideas?