krmiller07

I'd start by squirting or pouring a few onces of Marvel Mystery oil down the throttle body and then adding the rest to the fuel tank. Diconnect the or pull the fuel pump relay located on the passenger side fender in the engine compartment. The take all the spark plgs out and turn the engine over with the started to lossen up the piston rings and coat the valve sten seals. Put the spark plugs back in, reinstall the fuel pump relay and start it up and let it idle or try to keep it idleing until it's up to opporating temp.Don't race or rev the motor exsessively. It will probably smoke alot until the Marvel mystery oils burns away. While the pugs are out check or repalce them if neccasary and give the cap and rotor a good look as well. If every thing lloks good or has been replaced start driving it. Continue adding Marvel mystery oil to a the fuel evry fill up for about 3 tanks of gas. BTW thesee engines do not have 'valve gaskets' the have valve stem seals and valve cover gaskets. Another product worth using is 'Sea Foam' which is available from most auto parts stores. This too can be added directly to the fuel when filling up or by sucking into the intake system by disconnecting a vacuum line such as the one attached to the brake booster and slowly pouring the sea foam down the vacuum line or letting it get sucked through using engine vaccum while the engine is running. I use about a half a can, and then shut the engine off for about 30 - 45 minutes to allow it to soak into all the carbon deposits, the truck will smole for awhile after re-start but that will soon disappear as you drive it. Hope this helps.

Well, back to topic. Which of the BG products did you use? I know they have one that's added to the gas through the tank and one that is used in a dispenser as shown in the pic. I have a good friend who's a BG rep and he swears by the stuff. I actually let him use my rig as a test rig, and used both products as recommended and with him doing the work. I saw how much junk came out of the tailpipe as it idled in his driveway. I the added the fuel treatment to the gas with about a 1/4 to 1/8 from empty. When I left his house after driving it for a about 6 mile total initially after the treatment. I drove about a mile up the road and it stalled out. I let it set for a few minutes and cranked it over, only to have it run no faster than idle and then die. Long story short, I had to have the fuel pump replaced which is a story in itself. But after going through 6 different 'new' fuel pumps, all of which were NOT Nissan made, but were AC Delco pumps. I finally found one that worked IN the truck under load, as it turned out it was a Bosch brand pump which is still working fine. Now I don't know if was coincidence that the factory pump failed after the 'intake system' treatment and fuel additive or it was something in the chemicals that caused the failure. I do know my truck was laid up for nearly a week and it cost me a total of around $ 1600.00 in labor (pumps were still under warranty) to resolve the problem. I had heard other stories where the BG products work extremely well, and other stories where it started and created problems. Any opinions out there? I'm half tempted to try this stuff again, because it makes sense to clean the injectors and intake, valves, piston tops and combustion chambers out after alot of miles and varying qualities in fuels.

I'd have to agree. I'm wondering what contributed to the major improvement? The 3 M product or BG intake treatment?

Which should 'burn' off', leaving carbon deposits behind ?

bmcgawain, Where did you go to 'tech' school? Why didn't you just fill the intake system up with acetylene and light her off...after you take out full coverage insurance out on the truck. Transmission fluid....

If your still relying on that switch to change the way your truck rides...it's time for new shocks !

Were you driving the truck when you shot that video? I noticed your speedo was reading nearly 40mph (Electronic Speedo) while the tach was reading 2-2500 rpm. If the speedo is acting up at the same time, I'd say you definitly have an electrical issue or like Kingman mentioned above 'a ground' thats screwing things up.

Another 'dead nuts' on method of determining if your valves are bent. Is to do a cylinder leak down test. Just roll the engine over until BOTH valves are closed, and pressurize the cylinder (through the spark plug hole) and check the rate in which the cylinder in question bleeds off pressure. It also helps to listen to the end of the exhaust pipe for excessive 'whistling or hissing sounds. It may be difficult on vehicles with a cat, however if you have any bent or leaking valves, it's pretty obvious by the 'whooshing' sound pouring out the tail pipe. This kit sometimes comes with a compression testing kit. Keith

Come to think of it. My 85 300 ZX did the same thing. And I replaced everything from the CAS then the distributor to CTS and O2 sensors. Never figured out what caused it because I traded it for a New Pathy in 87. My 89 is starting to do something similar in that during warm up, once the temp comes up to about just off the 'C' on the temp gauge. The idle will kind of bounce or float between 800 rpm and 1000- 1100 like it's trying to figure out which speed it needs to settle into?

The O sensor harness comes up from underneath the truck and follows the firewall up the passenger side. There should be a connector in the middle of the wiring right behind the passenger side cylinder bank.

Your cold idle sounds way too high as well. Go back to the FSM and follow the instructions for adjusting these. Theres also a thread on here in the 'Garage' that details the different aspects and functions of the TBI system. I know these 'shouldn't' have changed, since the whole TBI and intake came off the old motor.However you have changed some of the key components. Double check your work!

I'm thinking it sounds more like a dirty injector dumping raw fuel into the intake. Try looking down the throat of the throttle body with the ignition key turned all the way on, but not far enough to engage the starter. You should hear the fuel pump pressurize the fuel system then 'click' off. Indicating you have reached proper fuel line pressure. If you look down the throat of the throttle body with a flashlight do you see any fuel squirting from an injector or smell excess gas? Also with the engine running, check to see if the fuel is vaporized in the Throttle body body, and not shooting a 'stream' of fuel down the intake.

Does it high idle only during warm up? If not, then simply turn the idle speed screw out to bring the idle speed down to around 800 rpm's with the fan switch on the off position. As for the 'smoke' or richness. You could have dirty or faulty injectors. I think I read somewhere on here that during idle and up to a certain rpm level, your only using one injector, after that rpm level is reached or exceeded, both injectors start supplying fuel. Just out of curiosity have you cleaned or replaced the spark plugs? You may have 1 or 2 that are partly fouled from the other problem. If it's hard starting, try checking and tracing the ignition electrical. Plug wires, cap, rotor and all the connections. Go with the simple obvious stuff first. Then check for vacuum leaks Just throwing that out there!

I know it sounds stupid, but is the fuel filter on the 'right'way? I'd also check the condition of the fuel lines and make sure none of them are collapsing, kinked or obstructed. It is possible you have a bad fuel pump. This happened to me a few years ago. I went through 6 'good fuel pumps' before changing brands, and settled with a Bosch fuel pump before the same problem you described was corrected. My truck would idle for as long as I wanted, however under 'load' or driving it would stall out and quit at exactly the same place while driving up the road. It was running the lines dry under load, but idleing it was fine.Stay away from the Airtex and AC Delco replacement pumps. I wouldn't recommend a Nissan pump either since they run about $700.00 from Nissan! Is your pump located in the fuel tank too? Hope that helps.

Sounds like a plugged fuel filter or faulty fuel pump. When was the last time the filter was changed ? When you say a couple of seconds, do to litteraly mean 2 seconds or after a couple of minutes? If it's running for a few minutes and dies then the pump probably isn't keeping up with demand or the filter is plugging on the 'outlet' side going to the throttle body or fuel regulator and is starving for fuel when the line runs dry.

Are the relays wired to a constant supply of power all the time...such as the battery? And the ground from both lights off the the new harness to a common ground. I'm still trying to get my arms around how this all ties into the factory harness and still supply power and the hi / lo beam switch from the turn signal switch? Plus how I can tie the low beam headlights and relays in with the factory fog lights. Anyone...anyone ! Beuler? Thanks

I for one have the same questions every one else has. I had some relays made because ebay and summitt no longer carry them. My questions are: how do you go about wiring in all of these new relays into the existing harness with out cutting into it and trying to figure out what head lamp wires your suppose to be splicing into AND retain the ability to keep a functional hi / lo beam switch? The ebay / Summit kit appears to have a male 9004 plug. Does that get plugged into the factory feamle plug that normally goes to the passenger side head light bulb? has anyone made a plug n play harness that allows you to do just what I described on both sides or head lights? I'm thinking 2 male 9004 plugs that go into the factory headlight sockets, and wire each side with relays that also contain a new heavier duty 9004 female socket going directly to their respective bulb, drivers side and passenger side. If anyone has actually performed this upgrade....please chime in...and include pictures! I'm confused and frustrated as hell trying to figure this one out. Thanks,

I agree with sewebster, Online i.e ebay you may spend around $300.00- $400.00 for all the parts. I have bought upper and lower ball joints on ebay for about $ 100.00 for both sides, tierod ends for around $ 100.00 etc... Buy a shop manual or download the FSM here and if you have some common hand tools, the job can be done in about a day (if you've never done this before) In my estimation the alignment would be the largest cost of this project. I have found that it's not the parts that are so expensive(providing you shop around online) but the labor to install them.

Mine did the same thing! Take it off and back. Then go buy a reman Bosch brand and you'll be done with it : ). The shop I went to was using every cheapo brand they could get a hold of. NAPA, AC Delco (worst) etc..

Try a salvage yard !

Especially if you run the engine backwards like they do in Australia ! lol

And theres a reason they're $20.00 ! They don't work !

My linkhttp://store.motiveproducts.com/round-universal-bleeder--0101-p60.aspx Try one of these. Best 'one man' bleeder out there. Keith www.frozenrotors.com

I agree with staying away for the Lucas Oil Stabilizer! I used the stuff on my last motor at the suggestion of a 'mechanic' and I threw a rod right out of the oil pan 200 miles later. No advances warning, No knocking...just a quick vibration through the steering wheel and A LOT of oil on the ground ! Spun all of the rod bearing's too. What was left in the pan, coated the sides like thick honey or STP oil treatment ! lol. I also later discovered that there are 2 types of the stuff. 1 for petroleum based oils, and one for synthetic, which is what I added to my Mobil 1 full synthetic. Either way, it was an exspensive lesson.

Nice heads ! Tell me more.