Search found 65 matches

by s24a
Sat Oct 28, 2017 8:57 am
Forum: TECH: 4A-GE ENGINE
Topic: AE86 Silvertop Misfiring Issue
Replies: 7
Views: 317

Re: AE86 Silvertop Misfiring Issue

BT ECUs are really not known for capacitor failures. I think Toyota/Denso wised up about the NICHICON electrolytics in the Silvertop ECUs. Not to say it cannot happen, but it is a rarer event. The BT ECU suffers from blowing the VVT transistor as a higher failure mode. As for doing either ECU and/or...
by s24a
Tue Aug 22, 2017 4:56 pm
Forum: TECH: 4A-GE ENGINE
Topic: 20V Blacktop intermittent misfire
Replies: 6
Views: 483

Re: 20V Blacktop intermittent misfire

Are you running an O2 sensor, and if so is it new as well?

If not, the vehicle may be finding lean spots in the volumetric efficiency maps.
by s24a
Fri May 12, 2017 6:23 am
Forum: TECH: 4A-GE ENGINE
Topic: Hi, 20v st (bt electronic)
Replies: 17
Views: 1652

Re: Hi, 20v st (bt electronic)

The Blacktop ECU is not as susceptible to capacitor failure as the Silvertop ECU is. The Silvertop Nichicon caps are basically junk. The blacktop uses a mix, so it is still possible some can fail. The Silvertop has a robust MOSFET VVT transistor, while the blacktop has a lower current transistor (sm...
by s24a
Thu May 11, 2017 12:51 pm
Forum: TECH: 4A-GE ENGINE
Topic: Hi, 20v st (bt electronic)
Replies: 17
Views: 1652

Re: Hi, 20v st (bt electronic)

The VVT should function without a speed sensor. The parameters for operation seem to be speed (RPM) and load (MAP sensor voltage and TPS position).
There is modification to operation points based on engine coolant temperature as well.
by s24a
Wed May 10, 2017 12:08 pm
Forum: TECH: 4A-GE ENGINE
Topic: Hi, 20v st (bt electronic)
Replies: 17
Views: 1652

Re: Hi, 20v st (bt electronic)

To quickly see if the solenoid is working, you can connect 12V to one terminal and ground the other while at idle. If the engine changes rpm and maybe also roughness, then the solenoid at least is working. As for the ECU, you need to take the cover off and look to see if the transistor in the center...
by s24a
Tue Apr 25, 2017 3:28 pm
Forum: TECH: 4A-GE ENGINE
Topic: Engine won't fire until I stop cranking? (Timing Issue?)
Replies: 16
Views: 1724

Re: Engine won't fire until I stop cranking? (Timing Issue?)

Just spoke to the guy who sold the diy to me a while back. Apparently this should be spring assisted. Must have come off... Hopefully it's not too tricky to fix. You have a fully electronically controlled spark advance. Which depends on a correct and CONSTANT ANGULAR POSITION trigger from a sensor....
by s24a
Tue Apr 25, 2017 4:30 am
Forum: TECH: 4A-GE ENGINE
Topic: Engine won't fire until I stop cranking? (Timing Issue?)
Replies: 16
Views: 1724

Re: Engine won't fire until I stop cranking? (Timing Issue?)

That distributor is a Bosch unit. Maybe they used them on some Ford Euro Pintos, but I really don't think so. It looks like it probably came from a VW/AUDI application as it is a head mounted distributor (I have one with identical reluctor setup in a Renault 807 crossflow engine in my Lotus Europa)....
by s24a
Thu Apr 13, 2017 8:04 am
Forum: TECH: 4A-GE ENGINE
Topic: Questions and Spark Plug covered in oil
Replies: 7
Views: 1109

Re: Questions and Spark Plug covered in oil

Here are a video that show basic construction details on the filters. Not sure of actual STP version you are thinking about, but the more premium version is better than the base model. Note that the FRAM is made completely of glued cardboard and has the least filtration media. https://www.youtube.co...
by s24a
Tue Apr 11, 2017 7:48 am
Forum: TECH: 4A-GE ENGINE
Topic: Questions and Spark Plug covered in oil
Replies: 7
Views: 1109

Re: Questions and Spark Plug covered in oil

Sgt Rauksauff I think answer question 1. For question 2 (what oil filter) the Toyota brand is one I use. BUT, I think any premium filter such as WIX or Bosch should also be good. Stay away from FRAM filters, as they are glued together and are prone to QC issues. :shock: Cut one apart to see what I a...
by s24a
Wed Mar 22, 2017 10:41 am
Forum: TECH: 4A-GE ENGINE
Topic: OST-043: Deutscher größerer Ventilkopf
Replies: 26
Views: 2690

Re: OST-043: Deutscher größerer Ventilkopf

With SV3 going out of business, what are you going to do for the future with regards to these exhaust manifold gaskets?
by s24a
Mon Mar 20, 2017 5:43 am
Forum: TECH: 4A-GE ENGINE
Topic: Bad fuel pump?
Replies: 7
Views: 935

Re: Bad fuel pump?

If the engine ran better overall in cold weather, and also runs OK when cold in the "warmish" temperatures, might not be fuel pump as cold engines/cold weather typically need MORE fuel so the pump would act up then. Have you looked at the ISC valve to make sure that it is functioning corre...
by s24a
Tue Feb 14, 2017 5:14 pm
Forum: TECH: 4A-GE ENGINE
Topic: engine wont start after warmed up normal driving
Replies: 11
Views: 1536

Re: engine wont start after warmed up normal driving

Might be vapor locking due to pressure regulator leaking (or maybe injectors). Throw a pressure gauge on the rail and after you start it, watch the fuel pressure. Then shut it off and watch the pressure decay. A good regulator/injectors will hold pressure for over 30 minutes or so. If yours starts t...
by s24a
Sat Jan 28, 2017 5:51 am
Forum: TECH: 4A-GE ENGINE
Topic: OST-043: Deutscher größerer Ventilkopf
Replies: 26
Views: 2690

Re: OST-043: Deutscher größerer Ventilkopf

Deutscher größerer Ventilkopf means literally German Larger Valve Head, or as slang, "Big Valve" head. So I am assuming that this head from Germany is different than the US version as it comes already with bigger valves? How about the port sizes/shapes? Are they the same or also different?...
by s24a
Mon Jan 23, 2017 5:05 pm
Forum: TECH: 4A-GE ENGINE
Topic: Tuning stock ecu
Replies: 8
Views: 989

Re: Tuning stock ecu

You might try carefully reducing the fuel pressure. You would have to acquire an adjustable pressure regulator if the one you have doesn't have an allen wrench adjuster (inside the vacuum port).
Be careful to make sure that the WOT A/F is still below 13:1 for safety.

Hank
by s24a
Thu Dec 29, 2016 3:11 pm
Forum: TECH: 4A-GE ENGINE
Topic: converting to fuel injection
Replies: 6
Views: 652

Re: converting to fuel injection

The type of sensors used will be dependent on the type of control system. For example, a GM system from the mid 80s to mid 90s used ECT and IAT sensors that were a NTC (negative temperature co-efficient) resistive type. Meaning that at cold temperatures the resistance was high, and at hot temperatur...
by s24a
Thu Dec 29, 2016 10:08 am
Forum: TECH: 4A-GE ENGINE
Topic: converting to fuel injection
Replies: 6
Views: 652

Re: converting to fuel injection

An engine control system will need to know the following: o What is the position of the crankshaft for timing injection. So need a crank sensor. You can use the four pulses from a distributor for that information as it is already going to the MSD. o Control system needs to know whether the engine is...
by s24a
Thu Dec 29, 2016 7:46 am
Forum: TECH: 4A-GE ENGINE
Topic: converting to fuel injection
Replies: 6
Views: 652

Re: converting to fuel injection

I guess my main question is what is the ABSOLUTE MINIMUM sensors I will need to run if I use an aftermarket manifold (mrp) and some aftermarket ecu. A typical speed-density setup like the 20V blacktop uses will have the following: o Crank sensor o Cam sensor (if you want sequential injection) o TPS...
by s24a
Sun Dec 18, 2016 5:57 am
Forum: TECH: 4A-GE ENGINE
Topic: 20v oil type question
Replies: 6
Views: 688

Re: 20v oil type question

Viscosity in multi=grade oils can be thought of as follows: Take your 0W-40 for instance. At room temperature (20ºC) the first number is the TRUE viscosity. Its a "0" weight oil. However, the viscosity improvers in the oil cause it to act like the second number when under heat and pressure...
by s24a
Sat Dec 17, 2016 4:51 pm
Forum: TECH: 4A-GE ENGINE
Topic: 20v oil type question
Replies: 6
Views: 688

Re: 20v oil type question

Another possible reason is that the viscosity of the oil affects the Oil Control Valve for the cam phasing.
Typically the clearances in it dictate the viscosity.
Too thin and too much leakage and slow response.
Same with too thick an oil.

Hank
by s24a
Mon Nov 21, 2016 4:18 pm
Forum: TECH: 4A-GE ENGINE
Topic: Rebuilt 4age bigport no spark
Replies: 42
Views: 4137

Re: Rebuilt 4age bigport no spark

Bit of a SWAG (Super Wild Ass Guess) here, but possibly the ECU has some issues? Have you taken the cover off and checked the electrolytic capacitors for any leakage or bulging ones that may have changed values due to deterioration? This is a BIG issue on 20V Silvertop ECUs, and also on Blacktop ECU...
by s24a
Fri Nov 11, 2016 7:24 am
Forum: TECH: 4A-GE ENGINE
Topic: Rebuilt 4age bigport no spark
Replies: 42
Views: 4137

Re: Rebuilt 4age bigport no spark

Well, if it was head porting residue, it would be aluminium and that is not magnetic. So I think you can eliminate that as the source, although pan sludge that does NOT stick to a magnetic could be porting residue if you see it in drain oil. I am going to place my bet on block hone residue. When you...
by s24a
Sat Oct 15, 2016 5:47 am
Forum: TECH: 4A-GE ENGINE
Topic: Rebuilt 4age bigport no spark
Replies: 42
Views: 4137

Re: Rebuilt 4age bigport no spark

I have also drained the first oil after the rebuild. Drove like 3 or so miles with it, but did idle with it a fair amount while I was setting up everything and testing. Oil was a solid gray color. I expected that because of the assembly lube. But it was also very thin, almost like water. I put it 1...
by s24a
Tue Oct 11, 2016 7:14 am
Forum: TECH: 4A-GE ENGINE
Topic: smaller alternator options?
Replies: 2
Views: 440

Re: smaller alternator options?

Don't know where you are located, but if in the USA/Canada, you can use the alternator off a 1.0L GEO Metro (US) or a 1.0L Pontiac Firefly (Canada) with NO A/C. This is a small Nippondenso alternator about 50A in output and has comparible sockets for most Denso alternators from Toyotas. It does have...
by s24a
Sat Aug 20, 2016 2:29 pm
Forum: TECH: 4A-GE ENGINE
Topic: 20v blacktop o2 sensor
Replies: 4
Views: 970

Re: 20v blacktop o2 sensor

The only requirement I know of for the sensor is to make sure the heater resistance is around 11 to 16 Ohms so as to not tax the drive transistor of the O2 heater circuit. Other than that, you can use any zirconia sensor with a heater (preferably four-wire) and a connector that matches your harness ...
by s24a
Sun May 22, 2016 4:14 pm
Forum: TECH: 4A-GE ENGINE
Topic: renamed: crazy oil leak from Valve Cover?
Replies: 30
Views: 3603

Re: renamed: crazy oil leak from Valve Cover?

Good find! Evidently the crushed baffle drains allow the oil that is flung up into the breather area to reside long enough to start spilling over into the tube. From there it goes wherever (catch can or back into the manifold). Why the baffle drains were closed up I guess is the $64K question. Maybe...
by s24a
Fri May 20, 2016 7:57 am
Forum: TECH: 4A-GE ENGINE
Topic: renamed: crazy oil leak from Valve Cover?
Replies: 30
Views: 3603

Re: renamed: crazy oil leak from Valve Cover?

Not that it might make a difference, but is that carburetor stock or an aftermarket type?

Hank Dozier
by s24a
Tue May 17, 2016 6:11 pm
Forum: TECH: 4A-GE ENGINE
Topic: renamed: crazy oil leak from Valve Cover?
Replies: 30
Views: 3603

Re: renamed: crazy oil leak from Valve Cover?

When you had the valve cover off, did you notice a lot of oil in the head, or was it fairly dry (thin coat on surfaces)? If there was a lot of oil, wonder if the drainbacks to the sump from the head are partially blocked. That would cause major oil splash and pushover from the vent. Might also expla...
by s24a
Sun May 15, 2016 7:52 am
Forum: TECH: 4A-GE ENGINE
Topic: 4age Silvertop 20v no diagnosis mode, erratic warning light
Replies: 10
Views: 1075

Re: 4age Silvertop 20v no diagnosis mode, erratic warning light

The capacitors do not have to leak to become unstable. Check them for bulging on the sides and top. That is a telltale the caps are failing and changing value. Don't know where you got that $200 for fixing an ECU from, but my charge for the Lotus guys is $85.00 USF for the work using "gold stan...
by s24a
Sat May 14, 2016 3:57 pm
Forum: TECH: 4A-GE ENGINE
Topic: 4age Silvertop 20v no diagnosis mode, erratic warning light
Replies: 10
Views: 1075

Re: 4age Silvertop 20v no diagnosis mode, erratic warning light

If you open the ECU, look at the capacitors on the board. Some of them leak the gel inside out onto the board, and this can also etch the traces as well causing opens and shorts. Other capacitors can "bulge", either the top swelling up or the cylindrical sides swelling out. All of the abov...
by s24a
Tue Mar 29, 2016 3:46 pm
Forum: TECH: 4A-GE ENGINE
Topic: renamed: crazy oil leak from Valve Cover?
Replies: 30
Views: 3603

Re: Valve Stem Seals, I think?

Does the oil itself look fairly clean on the valvetrain and on the dipstick? Or does it resemble the catch can crud? If the oil is filthy, sounds like its time to do an in-situ engine crankcase cleaning. Put a NEW filter on the engine, and change the oil to something like a 10W-40 or 20W-50 and in p...

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