Howdy all,
I just finished scouring all the topics on this forum but I could not find an answer to my problem. I have a 89 Dodge Colt Turbo 5 speed with only 112,000 Km's. I've replaced the head gasket (leak), distributor cap, plugs, fuel filter, fuel pump, air flow sensor, removed cat converter (resonator currently in place), decarbed engine, air filter. My problem is (besides not getting to the point) is that when I press hard on the accelerater the car starts to jump, surge, buck etc. Sometimes there is only a serious drop in power with mild surging but for sure every time I put my foot into it'll experience the above mentioned symptoms one way or the other. It also has starting issues (i.e. it turns over really well but will not catch and when it does start it will idle like it's gonna die for about 10 min). The hard start issue is independant of weather as it does it in the cold or heat. Also, this surging problem occurred before I replaced the head gasket so I don't think I messed anything up when putting it all back together.
I would greatly appreciate any help you can provide. This is a really cool site so I will also be lurking on a regular basis and hopefully in the future I can help out someone else in need.

Something similar happened to my car too.
Does it have an oxygen sensor ?

If yes, then take it out, put it for 30 mins in 95% alcohol and then put it back in.
By the sound of it, you have a fouled oxy sensor, and when you apply full throttle, you get a very rich mixture. Don try to clean it any other way, you will probably do more damage to it.

Hope this helps

Keep on boosting

axolotl

you says it's a turbo? for how old it is and to have that few kilometers is crazy.. if it's not an intercooled turbo then it's a possiblity that the turbos shot... and that should be your problem. say if you car had 212,000 then if the turbo isn't intercooled then it's gone for sure..

Yes what I typed was correct. It only has 112,000 Kms on it. The little bugger still goes like stink when it's not surging and bucking around. When I took the head gasket off and peaked at the cylinder bores they still had the cross hatching like it was just recently done. This is why I want to fix this problem, the little car runs like it is practically new. I am pretty weak knowledge wise on turbos so I'm going to say (with little confidence) that it is not intercooled. It does have an oil and coolant line running to it. Does that make it intercooled. Thanks for your time guys. I'll try the O2 sensor trick. Is there some way I can hook up a multimeter and test to see if it is OK?

Yes,

Have someone behind the wheel revving the engine.
Disconnect the oxy sensor, connect it to your voltmeter, when throttle is applied the readings should climb to around 1 V, when throttle is released then they should drop around to zero. Remember, that this happens really fast, so you might not be able to actually read the voltage, you only care if it goes up and down. The sensor wont be working if the voltage readings remain constant.
Note, that it takes 1-2 mins to reach its operating temp, so do a bit of a driving before you start this procedure

axolotl

Keep on boosting

What kind of spark plugs are you using
are you using the stock blow-off valve

eric@diamondstarracing.com

is your mirage turbo throttle body (TB) injected?
if so, none of these problems are your gremlin....
i have the same problem with my starion.
which uses the same TB system.
your problem is your throttle position sensor TPS for short.
check this with a digital volt meter, switch it to .2k ohms.
wires to connect to TPS ( located on base of TB,
and is about the size of a film cannister. check at the plug which will be on the passenger side of your TB )
are green/black tracer, green/red tracer.
with engine off, meter connected, open the throttle with your
hand (SLOWLY) if reading goes up then blanks out. the tps is bad
i just opend a spare i had. part of the circut board inside rubs off over time
causing a short in the TPS. thus telling the computer(ecu) the
engine is basicaly off, inturn cutting fuel supply ( can you say LEAN mixture,
or no mixture at all) if you dont feel confident on checking this part.
take the part/car to someone who can or have them come to the car.
these TPS's start going bad slowly over time, so continuous driving
you will notice normal drivability deminishing. mainly hwy driving limited to
80-90 mph or 65 - 70mph top speed, which takes a few miles to reach those speeds. right? if these are your problems then a new TPS is in order.
cheapest i found was $231.00 us dollars up to $247.00 usd online.
im talking with a few companies here in the states that might help make a rebuildable TPS, if so ill let you know


the 3rd wire will just give you a constant reading of 5.2 ohms or 0ohms

-Make sure you've put back the cam angle sensor the right way, these kind of problem can occure when its 180 degrees off.

-Gap your plug to .028.

-Make sure your plug wires are in good shape and not inverted.

-Did you tested your intake piping for leaks? a leak before the throttle body could do this.

-And last, make sure your coolant temperature sensor is plugged, if not, the ecu will see -40 farenheight as the coolant temp.... Quite cold hein? in this case the car would try to create a chole situation by sending more fuel wich will cause the car to run pig rich and not right. If that was your probleme, perform an oil change, your oil is gone because of too much fuel leaked through the piston rings.

does your colt engine look like this? or similar?
i think 87-90 use similar intake system.

Hi guys
Looks like I've got some catching up to do with respect to responding to your input.
1) ERIC_DSR: I believe I put Bosch plugs in there. Since I'm not sure about the blow off valve and nobody else has really tinkered around with this car I'm going to say "sure, I have a stock blowoff valve". I'd appreciate to know what it looks like (I'm really new to turbos but I'm trying!)

2)BDperformance: Aye, 'tis indeed a TB injection. Excellent suggestions by the way. I've suspected the TPS for a while but I never knew how to test it. I have a crappy Chiltons manual that is so vague and basic it doesn't describe such testing procedures. You've outlined it fairly well so I'm going to give it a shot now that x-mas festivities are complete. If you do come across a distributor for TPS by all means please send it my way or post it somewhere for all to see as well.

3) COLTMAX: did you mean if my temp sensor is plugged in? I will triple check but I believe it is. The manual said 0.028 - 0.031 so I'm pretty sure I did that.

sometimes the temp sensors will cause rough running.
90 % of your trouble lies in your throttle position sensor;
as we call them in the starquest world TPS or TPsensor.
ill have the part number later 2nite or 2mro for you.
if you dont want to go dealer, autozone can get them
as well as napa.com,rockauto.com though a lil more pricey
i paid 190$ for mine.

I was out playing around with the colt today. I tested the TPS as suggested by BDperformance and it checks out ok (each turn of the throttle resulted in a steady and increased reading on the meter). I still believe my problem is that the injectors are not firing or are doing so improperly. If I pour gas down the throttle body it starts immediately and runs for a few seconds. If I could get the **** thing started then I could deal with this surging problem. Any suggestions on why it turns over but does not start?

ok the TPS check out good.
heres a few more things to check

injector resistence - 2.0-3.0 ohms (this will be in your chilton/haynes manuel)
check across the terminals of each injector.

injector connections - turn key to on, when checking the voltage.
this reading i dont know either. have a friend to help move the wires close to the connector while checking, for bad connections.

injector resistor - on your colt, the resistor should be located on diver side
firewall, right above the coil. the resistence value i do not know.
call a dealership for this, as i dont know anyone who would know the correct value.

injector connectors - these might need replacing due to hot/cold transistion
that this type of plastic goes through day after day, season after season.
these can be sourced as a pocket item @ your local salvage yard, from volvo's
to 240sx,

last but not least, the most over looked part that can cause all
of these troubles

the ignition coil. a 20$ part, some last longer than most cars around others
only a few years.

A G54B in a colt? :bwekk:

I'd start with replacing the injector clips & cleaning the terminals. This car also has a EGR valve. Take some starting fluid and spray around the EGR valve while the car is running, if the engine picks up speed suddenly.... I'd say your EGR valve diaphram is probably shot. Thats a few things that could possibly be wrong also. Oh yeah, almost forgot!, injectors from a non intercooled Conquest & Starion will work great in your car.

Howdy all,
It's been a while since I have done any work on the Colt due to me being occupied with a motor swap on my daily driver (back in May/June) and getting married/honeymoon (Sept & Oct). I am now free of any obligations so I am ready to get at it once again.
Yesterday I checked the fuel pressure and it is greater than 30 psi (my gauge only went up to 30 psi). Feeling that this is adequate I focused on the injectors which checked out OK by having ~ 2 ohms of resistance on both. I then checked the voltage coming out of the injector connectors from the harness. One connector read ~ 8 volts, while cranking, and the other read zero. The connector that read zero has a black weather protector hood on it while the one that appears to be working is a light brown color. I have a couple of questions from this new information.
1) If one injector is not receiving a pulse would that prohibit BOTH injectors from firing? (as it sits now when I crank the motor fuel does not come out of either injector).
2) I am having a hard time finding a wiring schematic for the 89 Colt Turbo which would allow me to trace where the problem is. Is it simply checking the pinouts on the ECU or is there another area I should check inbetween the ECU and the injector connection?
3) Which pinouts on the ECU should I check and what kind of voltage should I expect to see for normal operation?
4)If anyone could give me a quick tutorial (or a link?) on how to check the pinouts with a meter on the ECU it would be greatly appreciated.