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hi all. i just brought a 89 iroc with the 5.7 it needed a fuel pump so i replaced that. but not the car wont start unless u spray starting fuel in the throttle. i changed the tps,coolant sensor. please help
Posts: 9 | From: new jersey | Registered: Jul 2008
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We need more information since it is impossible to do a trouble shooting procedure over the internet. Does it crank? Have you unhooked the larger of the two fuel lines coming up inside of the left fender, and had someone turn on your key switch to see if fuel comes out of the hose? (Put the hose in an empty can to catch the fuel first before turning on key switch.) Do you have a "check engine" light coming on and staying on? Did you check the 20 amp inline fuse in the harness a few inches from your battery? Did you check to see if you have power to that 20 amp fuse?
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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ok ill check all those things 2morrow.i did check the valve on the fuel rail and when the car is off a little bit comes out. when the car is started via sarting fuild alot of fuel comes out. and no the check engine light is off. but thanks again 4 ur help. let u know 2 morrow wats happens
Posts: 9 | From: new jersey | Registered: Jul 2008
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A lot of fuel coming out when running on starting fluid, means the fuel pump is working and the ecm is turning it on. That means everything I've mentioned is working. I just thought of something else. If your car sat for a long time with fuel in the tank with the bad fuel pump before you bought it, the gas in the tank may have gone bad like in the Stabil commercial. I don't know if the connection I'm going to refer to now is factory or something that our club mechanic/guru adds to our cars, but I have a pair of wires with plugs at the firewall near the ac box that will plug in to each other, but are normally unplugged. When plugged in they turn on the fuel pump in the tank. Some of the guys on this board may know if it is factory. If it is factory, unhook the larger of the two neoprene fuel lines on the left side of your car going to the fuel rail, and put the open end of the line into a 5 gallon fuel can. Plug in those connectors and it will turn on the fuel pump and empty the tank into the can. If you have more than 5 gallons in the tank, have enough cans standing by to hold all of the gas in your tank. As soon as the fuel stops flowing, unplug the line. Have a can of fresh gas available and hook up the line you unhooked and put in the fresh gas. Don't throw out the bad gas. You can burn it, but you need to dilute it with good gas. You can burn one or two gallons per tankful of good gas. The way to do it is to fill your tank. After you have driven 30-50 miles on the fill up, add a gallon or two of the bad gas to the tank. As you drive, the fuel returning to the tank should mix the bad gas with the good gas, and it will burn fine. The thing to avoid is a full shot of undiluted bad gas.
If the car still doesn't start, the next step involves checking the fuel injection system. I always recommend checking the easiest stuff before going to the harder tests. A year or 2 ago the club here in So Cal had a rash of cars that wouldn't start. I was helping out at our club's mechanic/guru's shop when the first of the problem cars was being checked out. We found that the fuel pressure regulator was plugged up with a gray paste that looked very much like never seize. I suspect it was aluminum oxide dissolved by the gas and carried to the regulator. We cleaned it out and the car ran fine afterwards. Don ran into the same problem with 2 or 3 other cars in the next month and cleaned the regulators. To my knowledge, the problem has not occurred since then on any other cars. It may have been a case of bad gas from one particular company. The cars that were infected were from different parts of town, so would not have filled at the same gas station, but might have filled with a bad batch of gas from the same company at different stations around the area. The other possible problem with the regulator is that it is not restricting the fuel flow and so the fuel is not building enough pressure for the engine to run.
The pressure regulator is located on a line that crosses over between the 2 fuel rails. I think it is right next to the fuel valve that you used to check for fuel pressure on your previous post. You will probably need to remove the plenum for access to the it. It should be held on by a fitting in the line on each side of it. After you remove the pressure regulator, you will need a small tamper proof torx bit. The tamper proof torx screws have a small pin in the center of the "star" requiring a hole in the center of the bit. I think the regulator is rebuidable. Take the torx screws out and check for foreign material plugging up the works or for a crack in the neoprene diaphragm.
The other possible problem is the fuel injectors or wiring to them. If you look at the plugs on the injectors, you will see two wires going to each one. There are three wires total in the fuel injection harness, a blue one, a pink one and the third will be either black or brown (I don't remember for sure). Our cars work by "batch firing" the injectors. The left bank all fire, then the right bank fires. One side of the engine will use the pink wire to fire the injectors, the other bank will have the blue wires firing the injectors. The black or brown wire is the ground. Make sure both the pink and blue wires get power when the engine is cranking or running. You can check it by unplugging an injector wire and hooking a test light between the "hot" side of the injector plug and ground. Don't pierce the wire with the point of a test light to check it, sure fire way to get corrosion started in the wire. Also be careful to use something as small as the opening in the plug for testing like a paper clip and test leads between the plug and the test light. What you want to see is flashing on the test light as the engine is cranked over. Check one injector on each side of the engine. Also check to make sure you have a good ground on the black or brown wire. I think the wires from both banks are put in one crimp connector and fastened to a lug on the fire wall or else on the back of the cylinder head. If the wires have broken out of the grounding terminal or rust has rendered the connection bad, that could be your problem.
The final check is the injectors themselves. You will need a fuel rail, both hoses, and an electric pump to check the injectors. You do not need the expensive high pressure pump from a third gen, just a pump that will pressurize the rail to allow fuel to squirt out when the injector is energized. You will also need a battery to power everything and some jumper wires. If you have a diy wrecking yard nearby, look for a six cylinder Camaro or Firebird with fuel injection and get the fuel rails, neoprene hoses, and electrical plug with a few inches of wire for each plug off it. The v8 injectors will install in the 6 cylinder rails and you just need to test them in two steps. Out here tpi systems from Third Gens disappear within minutes of the cars going into the yards, but 6 cylinder multiport fuel injection systems are plentiful. You just have to test 6 injectors and then remove 2 from the rail and install the other two for testing. You will also need a fitting to fit your fuel pump output to the supply hose, and another fitting and hose for fuel pick up and a coffee can to hold a little fuel for the test.
When you check out the injectors, you will do 2 tests while they are off the car. One test is to pressurize the fuel rail and make sure none of the injectors leak without being powered. If an injector leaks, it need to be replaced. If none leak with everything hooked up and your electric pump energized to pressurize the rails, then you need to check the operation of each injector. Install the injector plugs on each injector. Strip the end of each wire on the injector plug to allow you to clip on a test lead. Run a test lead from the ground wire to the ground side of your battery, and then a second test lead to the positive side of your battery. If you touch the positive lead to the pink or blue wire while the ground wire is grounded, the injector should spray with the fuel pump pressurizing the system. You test each of the 6 injectors, then remove 2 and install the two that have not been tested. If any of the injectors don't spray when energized, they need to be replaced.
One last caution, when you replace the plenum, some of the center bolts in the plenum are drilled at an angle. If you try to put the bolts in straight, they may screw right in, but they will be cross threaded! Put all of your screws in by hand first before final tightening, and you should get them in correctly. Also you are screwing into aluminum, just hand tight at the head of a ratchet is plenty.
Hopefully you will find your problem before you take your injectors out, but doing this entire procedure should pretty much check out your fuel system.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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One problem...so many variables....I was going to say check the 'cold start valve and related parts,' but, I think the 89s don't have this anymore?
Posts: 7773 | From: New Haven, CT USA | Registered: Jun 2001
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ok ill check the fuel pressure reg. i changed the fuel filter today and still nothing. but thanks 4 ur time
Posts: 9 | From: new jersey | Registered: Jul 2008
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Find the ground connection for the injectors. I think it is on the back of the cylinder head, but it may be on the firewall. Make sure you don't have wires broken from the terminal or a broken eye terminal causing you to lose the ground.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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hey russ i checked unplugging the fuel supply house and fuel did come out. so im goin 2 move on to the fuel pressure reg.ill let u know n a few dayswat happend
Posts: 9 | From: new jersey | Registered: Jul 2008
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hey russ do u have a pic of what the fuel injector termial looks likes? and i changed the capand rotor cause they were both rusty.i also change the fuel pressure reg, but still no change n the car
[ July 28, 2008, 08:45 PM: Message edited by: jose ]
Posts: 9 | From: new jersey | Registered: Jul 2008
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I'm not sure I understand what you are asking about. There is no fuel injector terminal. There is a plug on each injector. One side of the engine the injectors will have a pink and either black or brown wire. The other side will have a blue wire and the black or brown wire. It seems to me the ground is black, but I just can't remember for sure.
It just dawned on me after reading your last post that if the cap and rotor were rusty, you probably have a bad ignition module as well. The ignition module is just under the rotor where points were found on old school motors.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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I forgot to mention that when replacing an ignition module it is vital to put a coat of dielectric grease between the module and the base plate to make sure the base plate is a good heat sink. Failure to use the grease will result in the module overheating and premature failure.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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I wonder if thats the same stuff as the white grease used between power transistors and aluminum heat sinks?
Posts: 7773 | From: New Haven, CT USA | Registered: Jun 2001
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I think it is Sandy. Sometimes it is white, the points grease that came with your points back in the day was also dielectric grease and it was clear. I also had a bottle of black dielectric grease. The bottle died, but the grease is in another plastic container.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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I remember there are several different types of dielectric greases. I remember paying a whopping $10 for a tiny 2 1/2oz.? tube for the spark plugs at the dealership. Head my lesson and don't go there for this stuff. And I didn't even get my complimentary bar of soap!!!
Posts: 7773 | From: New Haven, CT USA | Registered: Jun 2001
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I got my 6 oz plastic bottle of the stuff at an electrical supply warehouse for $11.00. The bottle decayed and cracked long before I used up the grease. The grease is now in another container.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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hey russ i changed the dist. and it working better. a friend said it could be bad gas
Posts: 9 | From: new jersey | Registered: Jul 2008
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It could be bad gas. If the car has been sitting a long time, the gas could go bad, or it could be a load of gas from a station whose tanks were contaminated by water. Just unhook the fuel supply line, and jumper your fuel pump to empty the gas tank into a container. Then put fresh gas in the car. Don't throw away the bad gas. If it is just water in the gas, you can let the water settle out and take the gas off the top or put it in a container with a tap on the bottom to let it settle and pour the water off the bottom. If the gas has turned to varnish, you can still burn it in your car; but you need to dilute it by putting a gallon or so of the bad gas in the tank and filling it with fresh gas. If the fuel level is low, just fill up and let the new gas dilute the old stuff.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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hey russ we dumped all the fuel in the car and put another fuel filter in it. but it still not workin right. the pressure is only 30psi with the key on. so im goin 2 move on to the injectors. like u said. any other ideas to check?
Posts: 9 | From: new jersey | Registered: Jul 2008
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I think you are looking at needing a new fuel pump. The fuel pressure should be over 40#. To replace the pump, you need to remove the fuel tank. If you can get the car high enough in the air, I think you can remove the Panhard bar (Nascar calls it a track bar), unbolt the shocks, and remove the torque arm, the wheels, and the drive shaft. Then you just lower the rear axle with a floor jack supported by the lower control arms, and remove the springs as they come loose from the rear axle. If the car is high enough in the air, I think the axle will hang low enough from the lca's to get the tank out. The biggest consideration is to not force the tank. I know of a guy who managed to get a tank out of a third gen , replaced the fuel pump, and put the tank back in without removing the rear axle, but he forced it and broke loose the solder joint between the filler neck and the tank causing a leak.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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i changed it the pump already but i didnt go with a ac delco one. do u think i need to go with acdelco
Posts: 9 | From: new jersey | Registered: Jul 2008
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I would recommend the Delco pump myself, but the issue is not the brand. If you don't have 42# at the injectors, it won't work.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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The guy who works on my car replaced mine with a NAPA pump. I'm not thrilled with NAPA parts, but it seems to be holding up. This demonstrates that not having a ac delco pump doesn't mean it won't work right. But, it is possible to get a bad new part out of the box. My new MAF is a good example of that. And the failure wasn't immediate, either. It happened over about a month or 2 interval.
Posts: 7773 | From: New Haven, CT USA | Registered: Jun 2001
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I'm afraid that since parts production has moved overseas, quality is in the toilet. I used to prefer Napa parts to Pep Boys, Kragen, or Auto Zone for instance, but then my plastic heater control valve leaked big time blowing antifreeze everywhere under the hood. It was the original valve, so I went to Pep Boys, Kragen, and Auto Zone. They don't stock it since GM changed the design from a 3 hose connection valve to a 4 hose design. I went to Napa and they had the correct valve in stock, so I bought it. I installed the valve and it worked fine until I needed to turn on the heater. As soon as I asked it to turn on the heat, it failed big time blowing antifreeze all over the engine. I pinched off the heater hoses with the clamps I keep in the trunk for just that purpose, refilled the cooling system with water and took the part back to Napa for exchange. They exchanged it without question, but the next one did the same thing. I tried a third one, which also failed the same way. I decided that three defective valves in two weeks time was too many to let Napa have another try at getting it right. I went to the local Chevy dealer and bought a valve for about $30.00, if I remember correctly, instead of $15.00 and that valve has been trouble free for 3 or 4 years. The Napa part was made in China, the GM part was made in Mexico.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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I recently replaced my TPS. Pboys had a OEM Borg Warner. I was very pleased. It's just like my 18+ year old part. Must be new old stock (NOS). Parts made in china are very scary. Especially for a part that has to handle pressure or is located in a 'expensive' area.
Posts: 7773 | From: New Haven, CT USA | Registered: Jun 2001
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I have a stock 89 5.7 Iroc with 62000 miles and the temperature sensor and connection was bad and I replaced both and the car ran well for aproximately 3 months. Now it will start good and run til it gets to temperature and it starts to run rough and the idling begins to surge. When it does this, it wont start til it sets and cools aprox. 2 hours and it will start and run normal till it reaches temp again. Any suggestions?
Posts: 3 | From: Trinity NC | Registered: Nov 2008
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Does it turn on the "check engine light"? This doesn't sound like it is connected to your replacement of the temp sensor. It sounds like a leaking egr valve allowing exhaust gas to contaminate the air fuel mix when the engine is hot in closed loop. The other thing that comes to mind is a malfunction in the maf circuit either with the maf or the burn off relay. If it turns on the "check engine" light, pull the code and post it. If it doesn't turn on the light, it is probably a malfunctioning egr. You can check the egr by removing the line from the exhaust to the egr solenoid and plugging the line off. Then drive the car and see how it does.
-------------------- "Aerodynamics are for people who don't now how to make horsepower."-Enzo Ferari Posts: 1360 | From: Lakewood, Ca., USA | Registered: Jan 2002
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I was getting a code when I changed the temp sensor, but I am not getting any codes now. Thanks
Posts: 3 | From: Trinity NC | Registered: Nov 2008
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Those modules should probably be replaced now and then. They do tend to fail after a few years.
Posts: 7773 | From: New Haven, CT USA | Registered: Jun 2001
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