Danbob99 Posted September 13, 2004 Share Posted September 13, 2004 Treid to run a search on this; to little help, i got loads of just "fuel" related stuff... lately, as of yesterday, just about every time i really stomp on it, i hit some really bad fuel cut. Once, twice, few times, till i get off it, and its pretty violent. I've felt fuel cut in cars before, but this is quite alot rougher than others i've felt. I can feel small amounts of fuel cut at lesser loads, its tough to accelerate lately without hitting it. I think my timming may also be a smidgeon off because under heavy, heavy load i can hear what sounds like a little bit of detonation, but no Cel from the knock sensor? It sounds kinda like sand dropping through the downpipe. Do i need to adjust my timing? fuel pressure? i'm running 10psi on my turbo, intercooled. Help! Thanks, Dan Link to comment Share on other sites More sharing options...
Subarutex Posted September 13, 2004 Share Posted September 13, 2004 Dan, its the drop in temperature that is making the fuel cut worse. Link to comment Share on other sites More sharing options...
iluvdrt Posted September 13, 2004 Share Posted September 13, 2004 Mine has been doing this for a long time. I think its the maf sensor. Link to comment Share on other sites More sharing options...
garner Posted September 13, 2004 Share Posted September 13, 2004 hey danbob, I can't say I have an answer for you but this issue is something I'm familiar with. I think we talked about it at WCSS (Maybe I was ) And it is an issue that a number of people have delt with and one worth getting to the bottom of Mine has gone away mostly and I can't actually "show it" to anyone because it happens randomly. The only thing I've done since experiencing it is put in an adjustable RRFPR made by Bosch, sold as an MSD. It has allowed me to crank the FP up to 45 or so and it seems to have almost fixed the problem..... Have you tried disconnecting the "Boost Cut" switch? Probably did that a long time ago..... You might want to examine the fuel delivery system. Your description of sand down the down pipe make me think you probably want to check your turbo while you're at it garner Link to comment Share on other sites More sharing options...
Subarutex Posted September 14, 2004 Share Posted September 14, 2004 I talked to him earlier, after he posted, today. He mentioned he accidently put some 89 octane in. Which probally did it. I suggested he throw in the cheapest bottle of octane booster he can find. Just to see if that is the problem. Link to comment Share on other sites More sharing options...
[HTi]Johnson Posted September 14, 2004 Share Posted September 14, 2004 coughfuelfiltercough excuse me Link to comment Share on other sites More sharing options...
Danbob99 Posted September 14, 2004 Author Share Posted September 14, 2004 Fuel filter is good, just changed it a few weeks ago. Tried the octane booster, cheep crap sold at schmucks, didn't work all that great. The intensity of the cut has lessened, i don't hit it in first gear anymore, lately it's only been second, nearing 4,500 Anyone ever heard of using Toulene (spelling?) as an octane booster? commonly found at home depot or a paint store? Link to comment Share on other sites More sharing options...
oddcomp Posted September 14, 2004 Share Posted September 14, 2004 yes i have .. supposedly works well i suggest doing a google or vivisimo search on it first tho not sure what if any thing it does to the o2 sensor it will raise the flash point of gasoline so it does not ignite as easy as i recently mentioned to garner if he ever checks his email i got rid of fuel cut problems and also have solved the hi boost pinging seems the stock suby turbo ecu yes it does run a bit rich .. just cannot deal with raised boost and meter fuel very well i also run 10 psi and a not installed yet intecooler on cheap gas that i can afford and fairly decent ignition advance and do not get knock now.. reason being that i can figure .. i am now supplying enough metered fuel to the motor Link to comment Share on other sites More sharing options...
Danbob99 Posted September 14, 2004 Author Share Posted September 14, 2004 What do you mix it at? how much to a gallon? I'm really interested in experimenting with this, it souds like a really good idea... Link to comment Share on other sites More sharing options...
oddcomp Posted September 14, 2004 Share Posted September 14, 2004 i don't remember off hand it just alot of stuff i ahve run across in engine performance research i can try and dig up some numbers for ya if ya want but it won't be until tomorrow as its getting to be nap time for me Link to comment Share on other sites More sharing options...
Danbob99 Posted September 14, 2004 Author Share Posted September 14, 2004 The main ingredient in Octane Boosters is often Toluene (114 octane). The clever thing is that by packaging it in 6oz. containers and using the words Octane Booster, you can magically turn a $3.99 gallon of Toluene into an $85 a gallon gasoline supplement. Toluene is a pure hydrocarbon (C7H8). i.e. it contains only hydrogen and carbon atoms. It belongs to a particular category of hydrocarbons called aromatic hydrocarbons. Complete combustion of toluene yields CO2 and H2O. This fact ensures that the entire emission control system such as the catalyst and oxygen sensor of your car is unaffected. There are no metallic compounds (lead, magnesium etc), no nitro compounds and no oxygen atoms in toluene. It is made up of exactly the same ingredients as ordinary gasoline. In fact it is one of the main ingredients of gasoline. Toluene has a RON octane rating of 121 and a MON rating of 107, leading to a (R+M)/2 rating of 114. (R+M)/2 is how ordinary fuels are rated in the US. Note: toluene has a sensitivity rating of 121-107=14. This compares favorably with alcohols which have sensitivities in the 20-30 range. The more sensitive a fuel is the more its performance degrades under load. Toluene's low sensitivity means that it is an excellent fuel for a heavily loaded engine. Toluene is denser than ordinary gasoline (0.87 g/mL vs. 0.72-0.74) and contains more energy per unit volume. Thus combustion of toluene leads to more energy being liberated and thus more power generated. This is in contrast to oxygenated octane boosters like ethanol or MTBE which contain less energy per unit volume compared to gasoline. The higher heating value of toluene also means that the exhaust gases contain more kinetic energy, which in turn means that there is more energy to drive turbocharger vanes. In practical terms this is experienced as a faster onset of turbo boost. Toulene R+M/2...114 Cost...$4.00/gal Mixtures with 91 Octane Premium 10%...93.3 Octane 20%...96.0 Octane 30%...97.9 Octane You can make your own by combining Toluene with Kerosene in a 6:1 ratio and gain approx. 1.1 octane (RON) by adding 1 gal. to a 20 gal. tank of gas. You can buy Toluene in 1 gal. or up to 55 gal. from a Sherman Williams Paint store. Care need be taken when mixing it and storing it. Octane ratings can be very easily calculated by simple averaging. For example, the tank of an Esprit is 21.0 gallons. Filling it with 20 gallons of 91 octane and 1 gallon of toluene (114 octane) will yield a fuel mix of: (20.0 * 91) + (1 * 114) / 21.0 = 92.09 Found this on the "piston heads" website Figure i'll take tonight to go find me some Toluene...Sorry for spellin it wrong too! Link to comment Share on other sites More sharing options...
rallyman Posted September 14, 2004 Share Posted September 14, 2004 The problem sounds like the one various people have had over the years and people will for many more...You say that you are running 10psi ... You have a boost guage to read this then, if the cut happens after 5 seconds above 9psi then this is the ECU stopping you lunch the engine! If you have the air flow meter with the flap door sensor then this cut out can be over ridden by disconnecting one of the pressure switches by the AF sensor, (one does the dash lite for the turbo symbol the other is for the ECU) Otherwise if you have the "HOTWIRE" sensor I think that Skip is one of the few to have overcome this?!?!? You should get used to this counting to 5 if you are pushing the car! Michael Link to comment Share on other sites More sharing options...
oddcomp Posted September 15, 2004 Share Posted September 15, 2004 i overcame the fuel cut and maf in one shot Link to comment Share on other sites More sharing options...
Danbob99 Posted September 15, 2004 Author Share Posted September 15, 2004 Thats a good thought "rallyman" i guess all this did happen in close relation to me having plumbed my "boost light" though i don't have the flapper intake, i think that might still be along the same lines. i did though, try and disconnect that second vacuum selenoid on the right srtut tower. To my suprise...no more boost cut!!! Though heres the kicker...i also boosted at a minimum of about 18psi....i don't know how hi it would go, didn't want to try, got off it as soon as i saw it that high, and heard it begin to detonate... So why would unplugging that selonoid, and bypassing vac lines cause my boost to shoot through the freakin roof like that? And one more...i can't find any Toluene, searched a few stores, but alot were closed already, no luck though. Lots of Mek...can i mix that? Link to comment Share on other sites More sharing options...
oddcomp Posted September 15, 2004 Share Posted September 15, 2004 because one of those is a pressure switch that tells the ecu to open the wastegate solenoid ... so..no pressure signal being sent to ecu then the wastegate solenoid stays closed i bypassed my suby wastegate control system when i put my apc box in i only left the turbo light working .. actually i just stuck a bolt into teh orginal hose that went to the wastegate can to plug it and then hooked up the apc unit speaking of wich.. i need to change wastegate can's too the saab can it opens at 5 psi versus the 8ish that the suby can opens at it will allow my apc a bit more leeway in case it needs to drop boost to stop the detonation Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now